Bought too much purple sweet potatoes and don't know what to do about it apart from making the usual tong sui boiled with pandan leaves & ginger for a sweet dessert.
So I tried adding sweet potato when making Chiffon Cake.
Read some secret on how to make the purple colour from the sweet potato to remain purple or pinkish color on the cake. Lemon juice is the secret here!! Once you add lemon juice to the mashed sweet potato, you will immediately see it slowly turns into pinkish colour. Otherwise, once you steamed the sweet potatoes, it will turn greyish colour and color is dull. I realised some purple sweet potatoes will turn greyish while some won't.
Ingredients: (17cm chiffon tube pan) (A) 100g purple sweet potato (steam and mashed) 3 tbsp milk
1 1/2 tbsp lemon juice (B) 3 egg yolks 20g sugar pinch of salt 50ml corn oil 4 tbsp water (C) 85g self raising flour (D) 4 egg whites 50g sugar 1/2 tsp cream of tartar Step by Step:
1. Thinly sliced sweet potato. Steam sweet potato for about 15 mins or until it soften.
2. Add milk & lemon juice to it and use a fork to mash till fine. I like it with some small bits of sweet potatoes.
3. Mix all ingredients in (B) till well blended. Add in mashed sweet potato and mix well. Sieve in (C) and mixed till smooth and lump-free.
4. Beat egg whites in (D) till foamy, Add in cream of tar tar & sugar in 2 batches, continue beat till stiff and glossy peaks formed. You should be able to hold your bowl upside down without the egg whites falling out.
5. Add half portion of egg white mixture into egg yolk mixture and mix well with a spatula until no egg white streaks remain.
6. Pour egg yolk mixture into the remaining white and mix till well-combined until no streaks remain.
7. Pour the batter into the ungreased pan. Bang the cake pan a couple of times to release air bubbles in the batter.
8. Bake at 180C at the lowest rack for 30 minutes or till cooked.
9. Remove from the oven and revert the cake pan upside down to cool down.
10. When the cake is completely cooled, gently run a plastic knife around the rim of the cake and then remove cake from pan. (I accidentally pulled the cake when unmoulding the cake, causing a big hole on the top :( too excited wanna taste my cake)
Look at that tiny bits of purple sweet potatoes. Isn't it looks nice!! Nom Nom Nom..