Friday, 29 October 2010

Purple Sweet Potatoes Chiffon

This must be the longest October for me.

I spent the first two weeks of the month sourcing for renovation contractors, reading up on renovation, visiting tile shops to select tiles, shopping around for lighting, bathroom sanitary ware, cooker hobs, oven, etc, etc. This is in preparation for my upcoming renovation of our house. The next two weeks were spent packing, packing and packing. On top of that, it was an anxious week when my elder son took the PSLE examination. I am glad that all went well, but before I could take a breather, it was soon my younger child's turn to sit for the year end school examination! Finally, his exam is over today. I am not done with packing yet...I still have to conquer the kitchen...which I have no choice but to leave to the last.

Anyway, I miss blogging...so I am here to share with you yet another chiffon cake recipe, before I dismantle my desktop computer and pack it into boxes.


This chiffon cake was made with purple sweet potatoes. I have came across two types of purple sweet potatoes...one of which comes with purple skin but the inside is yellow...and the other with both skin and the inside purple. This chiffon cake was made with the latter. It was by chance that I bought a bag of purple sweet potatoes. I actually wanted to get some spring onions and nothing else...but I was too shy to ask the stall owner. So I looked around and spotted the sweet potatoes...in the end I only paid for the sweet potatoes and the stall owner gave me the spring onions for free (^^')

There was no surprises when I went about preparing this chiffon cake. Although I must say, it was like attending some Chemistry lesson. I was amazed that the egg yolk batter, which was a deep purple because of the sweet potatoes, turn into a pretty pinkish batter the moment the few drops of lemon juice was added to it!

After the past few experiments in making chiffon cakes, I was quite satisfied with how this one turn out. The cake rose well in the oven, and it didn't shrink too much upon cooling :)


A few readers have asked me how I managed to unmold my chiffon cake nicely.  This time, I made it a point to take step by step photos to show all of you. I guess, the trick is to use a very thin bladed knife. When running the knife inside the cake pan, try to slide the knife as close to the inside of the pan, avoid slicing the cake crumb. I am not sure whether it is because of the quality or the type of cake pan that I am using, I am able to remove the cake effortlessly, without creating any mess. See photo 3 above...upon unmolding, there were not much crumbs left inside the pan.

I think it is also the type of cake pan that I am using, I always end up with chiffon cakes with 'pork-floss' like crust.


This chiffon cake was very soft and moist. The crumbs was a light pink...if the lemon juice were to be omitted, the crumbs would end up dull purplish. It was a fun experiment for me! This cake tasted really good, but I would still rank that banana chiffon cake as the best chiffon cake I have ever made ;)

I won't be sharing any baking post for the next two months as my kitchen is officially closed for renovation starting from today. However, I will still try to update my blog...but it will probably on the progress of my renovation or the holiday trips that we have planned.
 



Purple Sweet Potato Chiffon Cake

Ingredients:
(for 17cm or 7" tube pan)
(measurements in brackets are for 20cm or 8" tube pan)

40g  (70g)    egg yolks
50g  (80g)    water
40g  (70g)    vegetable oil
7g    (12g)    lemon juice
54g  (90g)    purple sweet potato, boil or steam, mashed
50g  (80g)    cake flour
10g  (20g)    caster sugar
70g  (120g)  purple sweet potato, boil or steam and diced into small chunks


110g (180g)  egg whites (cold from fridge)
55g    (90g)  caster sugar
5g     (10g)   corn flour

Method:
  1. With the skin on, either boil with water or steam the purple sweet potato till soft (test with a fork, it should be inserted easily into the centre of the sweet potato). Leave to cool slightly and remove the skin. Mash and dice into small chunks accordingly.
  2. Sieve cake flour, set aside. Sieve corn flour, set aside. 
  3. Place egg yolks, water, mashed sweet potatoe in a mixing bowl. With a manual hand whisk, whisk the mixture to combine. Add in the vegetable oil, stir to combine. Add the lemon juice and stir to combine. (Note: the mixture will turn into light pink.) Sieve over the cake flour and whisk till the flour is fully incorporated and the mixture becomes smooth and sticky. Add in caster sugar, stir to combine.
  4. In a clean, dry mixing bowl, beat egg whites with an electric mixer on low speed until mixture becomes frothy and foamy. Turn to high speed and gradually beat in the sugar, 1 tablespoon at a time, add in the corn flour together with the last tablespoon of sugar. Beat until the egg whites reaches the soft peak stage.The soft peak stage is reached when the peaks of the whites curl over and droop slightly. The egg whites should appear smooth and glossy. (Do not over beat the whites still stiff, it is better to beat the whites still soft peaks for easy folding with the yolk batter.)
  5. Add the beaten egg white into the egg yolk batter in 3 separate additions, each time folding gently with a spatula until just blended.
  6. Add the sweet potato chunks. Stir gently to combine.
  7. Pour batter into a 17cm tube pan (do not grease the pan). Tap the pan lightly on a table top to get rid of any trapped air bubbles in the batter.
  8. Bake in pre-heated oven at 160 degC for 35 mins, (for 20cm pan bake for 50 mins) or until a skewer inserted into the center of the cake comes out clean. (When lightly pressed the cake will spring back). Remove from the oven and drop the pan at a height of 20~30cm onto a table top. This action helps to keep the springy texture of the cake when it is left to cool.
  9. Invert the pan immediately and let cool completely before unmould. To remove the cake from the pan, run a thin-bladed knife around the inside of the pan and the center core. Release the cake and run the knife along the base of the pan to remove the cake.
Recipe source: adapted from 戚风蛋糕秘法传授 by Noriko Ozawa





Sweet Potato on FoodistaSweet Potato

54 comments:

  1. Beautiful chiffon cake!

    ReplyDelete
  2. I love your chiffon, always so nicely brown and
    "pork-floss"... :)

    ReplyDelete
  3. though i dun really like sweet potato chiffon but i must say i love the color and the color of ur chiffon is beautiful.

    ReplyDelete
  4. Very lovely colour chiffon HHB. Just in time for me to try out using sweet potatoes.

    ReplyDelete
  5. A soft and light chiffon cake with a touch of purple sweet potato, indeed very beautiful chiffon cake you had baked. :)

    ReplyDelete
  6. Very pretty chiffon cake! I also like your 'pork-floss' like crust.

    Why do you need to dismantle your desktop computer? I thought only your kitchen is undergoing renovation.

    I will miss all your bakings. Meanwhile, time to look through and try your old recipes. :)

    ReplyDelete
  7. This is nice....I remember my aunt made this quite sometimes ago and the feedback was good. Probably I should give it a try too. Thanks for sharing..:)

    ReplyDelete
  8. Thanks for sharing! Very beautiful chiffon cake with that diced purple sweet potato in it.

    ReplyDelete
  9. Your chiffon cake always look perfect. Coincidentally, I am looking for a sweet potato chiffon recipe. Thanks for sharing. =D

    ReplyDelete
  10. SSB, I am doing a major renovation to my whole house, not just the kitchen. Every corner of the house is affected, it's going to be an overhaul. Wish me luck!

    ReplyDelete
  11. Been wanting to bake this chiffon cake for ages, but purple sweet potatoes are so hard to come by!

    All the best in your renovations and looking forward to new posts from you.

    ReplyDelete
  12. Ooh! missed your blog so much! Very beautiful chiffon!

    ReplyDelete
  13. I lurrve your blog and so inspiring that all the beautiful creations came from a hand held mixer. All the best for your reno!

    ReplyDelete
  14. Congratulations on your new house! I like this sweet purple chiffon, must find some purple potato to try this.

    ReplyDelete
  15. Nice chiffon! Thanks for sharing with us how to unmold chiffon cake from pan, I think my knife is not sharp enough, till lots of crumbs still attaching to the pan.

    ReplyDelete
  16. I was still wondering why there was no post from you.... happy renovation o(o,O)o
    Always love how neat your chiffon cake is! And thanks for showing the pics on how you do it.

    ReplyDelete
  17. wow...I am speechless on your yummy pastries!

    ReplyDelete
  18. Hi HHB,
    i was wondering if you could troubleshoot my chiffon cakes. When i bake them,the surface always cracks and i get a dense layer just underneath the crack. It's quite like your blueberry chiffon a long time ago. Do u happen to know why , and what i could do to rectify it? THANKS so much in advance!

    ReplyDelete
  19. Beautiful chiffon. I wish I can bake that well. Want to come over and teach me this?

    In the meantime, have fun.

    ReplyDelete
  20. Hi, I've admired your baking skill since I first came across your blog site. I also looked forward to and enjoyed reading your post.

    I will try to bake a chiffon cake soon and look forward to trying out with your recipes soon.

    I have one question that I would like to ask you about cinnamon rolls. I just finished baking it. It tasted great and I'm quite satisfied with the taste. But I wonder why the sliced rolled dough won't rise high and it kind of expanded sideways instead. Is it supposed to be that way? The cinnamon rolls that I bought ready baked from the stores always looked like they have risen high but mine stayed the same height. Appreciate your input, please!

    Reinnie from Penang

    ReplyDelete
  21. lovely. Hope your re-fit goes well and look forward to more posts in a couple of months. Take care

    ReplyDelete
  22. Hi crustabakes, I am sorry, I don't think I have the skills nor the knowledge to help you trouble shoot. But base on what my previous attempts with baking chiffon cakes, if I assume that the beating of the egg whites, the folding of the whites to the yolk batter are all done correctly, then, it could be due to the oven temperature. Maybe your oven is too hot? The exterior gets baked really quickly and starts to 'set', subsequently, when the inside starts to expand it will cause the surface to crack. The hot oven may cause the exterior to get cooked and browned, while the inside is still dense and wet. What temperature do you usually bake your chiffon cake? Maybe you can try bake it at a lower temperature? For this recipe/cookbook, it is baked at 160 degC...while most other recipes will recommend 180 degC. I hope I am not misleading you in any way.

    Hi Reinnie, I think it is due to the type/size of the baking pan that you are using. What is the size and depth of the pan you are using? Use a smaller but deeper square pan so that the dough will not have room to expand side way, with a deeper pan, the dough will expand upwards...hope you know what I mean? For that cinnamon rolls recipe, I used a 20cm square pan.

    ReplyDelete
  23. Good luck with your renovations, look forward to your new posts in your new kitchen! :)

    ReplyDelete
  24. Don't overwork yourself, yea? I myself didn't bake and cook anything for the last 1.5 months due to relocation to the new house. Only starting to get back on track now, trying to get used to the new setting. A bit awkward, though, I must say. Thank you for the email btw. =)

    I've had purple sweet potato chiffon before. I love its sweet smell.

    ReplyDelete
  25. Finally see your posting! wow looking forward to your newly renovated kitchen. This purple chiffon is perfect! :) I always wanted to try new variations but my mum likes only pandan so I made pandan chiffon most of the time. Today I just made two, out of two different recipes. It's so theraputic after having missed baking cakes for a long time.(Baking bronwies dun count) ;)

    ReplyDelete
  26. HI HHB, I think i am just going to experiment more with different temperatures then. Thanks so much for the advise!

    ReplyDelete
  27. You have a beautiful chiffon cake! Can never bake as nice looking as yours! May i know where did you buy this chiffon book by Noriko Ozawa?

    ReplyDelete
  28. HHB, you are really master of chiffon cake, your chiffon are so soft, fluffy and nice baked!

    ReplyDelete
  29. I've never heard of this before and makes me wonder what else could go into a chiffon. I do like the texture and colour of the slices. Very pretty.

    ReplyDelete
  30. love the idea of sweet potatoes in the cake! Good luck on your home renovations... enjoy your holidays :)

    ReplyDelete
  31. Janice, I don't own this book, I borrowed it from a close-one.

    ReplyDelete
  32. This must be the first time I've seen sweet potatoes in a cake- how intriguing!

    Good luck with the move, HHB, and have a safe trip!

    ReplyDelete
  33. Hi! Came across your blog from a forum... What attracted me was the pizza recipe.. But after going thru your blog, i am not only trying the pizza, but a lot more of your recipes!!

    ReplyDelete
  34. its me again! since my 1st comment, i have been looking thru your post.. think up to march 2007, and i am supposed to be working!! had to make a trip to cold storage to get the stuff to make the pizza, and i cant wait to get my hands on it! all your postings really me feel like staying at home and baking all day long!! hahaha

    ReplyDelete
  35. Hi HHB, Thanks very much for your input. Actually, I work in a college where we have a culinary school. I asked one of our cooking instructor the same question. And his advise was exactly the same as yours. At the same time, he also advised to spread maple syrup on top of the baked rolls. In fact, nothing else (I tried spreading honey mixed sugar syrup) can compare with maple syrup. Well, I thought I'll share this info too.

    I baked Banana Chiffon cake 2 days ago. My son & I finished more than half the cake within half an hour. It was delicious. Many thanks to you for the recipe.

    Cheerio! Enjoy your evening ya!

    Reinnie, Penang.

    ReplyDelete
  36. a lovely cake you have there.. im not so good in chiffon cakes as i always make a blunder between steps 4 and 5 - the turning over part where i can't seem to catch hold of the cake when it falls. so my cake falls apart :S

    nice recipe here hope i can try and do it myself soon. happy reno! im also going to have a new home with new kitchen new oven and equipment..maybe you can share some tips n advice when choosing oven. im worried of getting one that cannot perform.

    ReplyDelete
  37. That's a perfect chiffon! Very tall and fluffy.

    ReplyDelete
  38. wow! purple sweet potato cake sounds divine!

    ReplyDelete
  39. What a fun cake! I love the color, and it's such a unique idea! I never would have thought to use sweet potato, let alone purple! I looks like the perfect chiffon cake though, so tall and light! YUM!

    ReplyDelete
  40. Mmmm.. this looks amazing! So fun and vibrant!

    ReplyDelete
  41. I just recently discovered your blog as I've been tirelessly trying to look for a sponge cake recipe, I'm a novice baker. I was thrilled to have found your site. It is very helpful and please expect my queries about your recipes in the future. As I live West, I will make it a point to go to Singapore next year and check out the stores where you usually buy your baking needs. Thanks and I wish you and your family well always!

    ReplyDelete
  42. HHB, i baked this the other day. Indeed very nice! Love the soft and moist texture of this chiffon. Thanks for sharing!

    ReplyDelete
  43. this blog is great! I already tried it and my whole family love it. nice color, its my unica ija's favorite color, purple.. thank you for sharing it to public. :)

    ReplyDelete
  44. I came across your site from the foodieblogroll and I love this recipe.I'd love to guide Foodista readers to your site. I hope you could add this sweet potato widget at the end of this post so we could add you in our list of food bloggers who blogged about recipes with sweet potato,Thanks!

    ReplyDelete
  45. Hi Alisa, thanks for the invite! I have added the widget in my blog post :)

    ReplyDelete
  46. Hi I'm always wondering how do you count da ingredients measurements correctly for different size of pans ? Most recipes created with different size of pans and I have da only 7' pan to work on..

    ReplyDelete
  47. hi Cassie, I didn't work out the ingredient amount. I followed the exact amount from recipe books (I will state the amount I used if I don't follow the recipe, usually, I will cut down on the sugar). I only have a 7" chiffon pan, many Japanese cookbooks use this pan size. It is best to follow the recommended pan size.

    ReplyDelete
  48. I tried this cake last saturday. The cake slid off the pan when it overturned. so sad but was a good experiement too and fortunately it was still edible and I suspect I must have overmixed when folding the egg whiltes. Even though it didnt turned out well, it was a very soft and nice cake. Will try again. thanks for sharing.

    ReplyDelete
  49. Hi Yummy Bakes, oh dear, it must have been one of those days when kitchen mishaps strikes...luckily the cake was still edible. hope you have better luck next time, cheers :)

    ReplyDelete
  50. Hi HHB! Love all your chiffon cake. I'm starting to bake cakes. I'd like to try your chiffon just wondering what size of cake pan I will use in your ingredients to create at least 3 layer cake and not using chiffon pan? Will it rise? Have you tried baking your chiffon cakes in regular cake pans?

    ReplyDelete
  51. Hi Ela, I have replied your queries earlier in this post:
    http://happyhomebaking.blogspot.sg/2009/06/lemon-chiffon-cake.html

    Here's my reply earlier:
    'I have not tried baking chiffon cake in normal round pan. However, I have tried using the same separate eggs method as chiffon cake (beating of egg whites and yolks separately) for a birthday cake which is baked in a cake pan (http://happyhomebaking.blogspot.sg/2012/06/cake-for-special-occasion.html)
    I don't think the portion (3 yolks, 4 whites) will yield 2 pans. I baked in 1 pan but cut the cake into 3 layers.'
    Hope this helps.

    ReplyDelete
  52. Hi HHB
    I tried baking this today and it tasted great. But my sweet potato didn't turn purple even after adding lemon juice. Not sure why.

    ReplyDelete
    Replies
    1. Hi I think you have misread my post. I used purple sweet potatoes, the lemon juice will not change yellow sweet potatoes into purple...however, the purple batter turned pinkish when i added in the lemon juice.

      Delete
    2. Oh thanks for the clarification. This cake tasted very moist and flavorful. I will bake it again!

      Delete