I've always had a quiet obsession with this cake, not because I really love green tea or adzuki bean, but because of Keiko Okashi: Sweet Treats Made with Love. The pictures inside the book really inspired me on Japanese chiffon cakes, even though I had never really been a great fan (except of course, pandan cake). It's just that for me, I associate some cakes with being light and fluffy, like pandan cake, or the steamed brown palm sugar risen malay cake (Malai kou, in Cantonese dim sum), but other flavours like orange or chocolate or lemon, no, give me a proper slice of crumbly, crystallised warm goodness, anyday!
While processing some chiffon cake recipes to look for those who had risen, even and tasty looking products, I discovered that there was a Bake-off challenge that involved chiffon cakes and that was it. Beetroot chiffon cakes- oh my, I didn't even know that a heavy ingredient like beetroot could be blended into a chiffon cake. And taro chiffon cakes (a beautifully and delicate purple hue) and coffee cakes and dulce de leche cakes, you can find the list here. Of course, in the end, it led me back to the green tea and adzuki bean cake.
So somehow, when looking to make a cake to complement an Asian dinner and also to use up my store of ingredients (always a challenge), I drifted back to the same few choices of leftover fridge ingredients and landed on one that was none of those. At least I had the whipped topping, so it wasn't a complete waste and I did manage to finish an entire can of adzuki bean.
That entire can, wound up being enough topping for three chiffon cakes, so after making one cake on Friday night, that was promptly demolished by the party that came to dinner, I wound up making another cake on Saturday for the family and then a third cake on Saturday, to give away. It was good practice, and an opportunity to iron out all the kinks while the knowledge was fresh in my mind, so now I think I have this recipe and the technique pretty much down pat.
Also, please know from my experience now, that 1 cup of whipped topping and 1 can of adzuki beans = three cake frostings for a 20cm bundt. After washing out my bundt pan for the third time, I concluded that I need another bundt pan of the same size. I have a 20cm tin and a 24 cm tin and the volumetric difference is huge. (The 24cm is so large that it is simply impactical for home-use and I have not even touched it much). This recipe will fully occupy a 20cm tin and it will rise to an impressive but manageable 4 inch height, but in a larger tin, it's just completely insipid.
The recipe that I use is adapted from, but not exactly as listed, in Okashi's book.
70g cake flour
5g Green tea powder (this is listed as 10g but I don't like such a grassy, jasmine flavour in my cake. Also please note that this has to be green tea powder and not just finely-ground green tea)
10g Corn flour
5 Egg yolks
20g Caster sugar
60g Canola oil or corn oil
Bowl C: Meringue
70g Caster sugar
6 Egg whites
1/2 tsp cream of tartar
1) Before you start, preheat oven to 160C. This is a fairly quick recipe to execute.
2) Combine egg yolks and sugar in a bowl and mix well. Add water and corn oil and blend together.
3) While the egg yolks are beating, sift the flours and the green tea powder together twice. Twice is important, so that it is fine. Add the flours and green tea powder mixture and until just incorporated, even and slightly sticky. Set aside.
4) Make the meringue by beating the egg whites until foamy and then adding the sugar and cream of tartar. Make sure your eggs are at room temperature and that your equipment is clean of any grease, to ensure the best result. Also, if you want to omit the cream of tartar, you can. I find that it helps me to stabilise the egg white and also reduces the size of the air bubbles and keeps them more even but some people feel that the cream of tartar has a sour, even metallic taste.
5) If you are really efficient, you can beat the egg whites first and while those are beating (as it takes the longest amount of time, within the recipe), prepare the egg yolk and flour mixture. By doing so, you cut your preparation time in half, as opposed to doing this step by step, but you should not leave the egg white mixture, once beaten, out for too long as the bubbles may start to soften and subside back into liquid.
6) The quality of your egg white is very important, if it is so fluffy, tight and foamy as to be almost solid, then you are guaranteed a lovely texture. If it watery, with large tepid bubbles that start to pop before you even mix in the flour, then you have a problem and will probably have a liquid thin batter that starts to seep under the groove of your bundt tin.
7) Lower the speed at which your egg white is beating and pour in the green egg mixture gradually. Do not overmix, stop the machine when all the batter is incorporated. Your batter should still be light, fluffy and thick. Conventional wisdom is that you should mix in one-third of your egg white into the batter, to keep it thick and aerated, and then fold in the remaining of the egg white, but I've found that adding the batter to the egg white, while the egg white is beating, has the same effect. You must however, never add the egg white to the batter while the batter is mixing. The egg white will deflate almost straight away.
8) Pour into the tin, spread evenly and bake for 45min-1 hour. I find it helpful to place my bundt on a baking tray, to make keep things neat.
9) Take the cake out of the oven and cool it, upside down, still in the pan. Do not attempt to cut the cake out before it is entirely cooled.
10) Slice cleanly around the edges of the pan before attempting to pop out the cake. Slice the top of the cake cleanly off the pan base.
11) Mix the cream topping with the adzuki bean and spread it on the sides and top of the cake. I find there is no need for sugar, as adzuki is naturally sweet. Some people add a little pink or red food colouring to achieve a prettier hue but I don't think it's necessary. When you cut the cake open, there is a lovely contrast between the pale pink exterior and the dusty green interior and the contrast of sweet, cold, bean-y and astringent, is just sublime, while still being light and refreshing.