Purple Sweet Potato Chiffon Cake 紫薯戚风蛋糕

Purple Sweet Potato Chiffon Cake 

      Ingredients:
      70g plain flour (sift together with corn flour)
      2tbsp corn flour
      3 egg yolks (about 55g)
      40g sugar
      60ml fresh milk
      1/2 tsp lemon juice
      100g purple sweet potato, mashed 
      60g purple sweet potato, cubes
      50g canola oil

      Meringue
      4 egg whites (about 165g) 
      1/2tsp cream of tartar
      45g sugar

     Method:

• Wash and peel the sweet potatoes, cut into small chunks. Steam sweet potatoes for about 15 minutes  or till soft. Blend 100g with 60ml milk to smooth paste. Dice remaining sweet potato to small cubes, set aside for later use.
• Preheat oven at 165 deg C. Sift flour and corn flour together into a bowl and set aside.
• Combine egg yolks and sugar in another bowl, mix well. Add sweet potato paste and lemon juice, mix well followed by oil and blend well. Sift in flour mixture the second time into egg mixture, mix well. 
• Make meringue – Combine sugar and cream of tartar. Beat egg whites until foamy. Add sugar mixture in 3 separate rounds beat until egg whites are glossy, with stiff peaks.
• Fold 1/3 of egg whites into the yolk mixture. Then pour in the rest of the egg whites and fold gently until combined with a rubber spatula.
• Pour 1/2 batter into the prepared a 21cm tube pan and sprinkle sweet potato cubes over it and cover with remaining batter . Gently bang the pan on the table top to release air bubbles. Bake at 2nd lower rack in the oven for about 50 minutes.
• When the is done, remove from oven and turn the pan over. Leave cake to cool in pan.
• 
  

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紫薯戚风蛋糕

    材料：

     70克 普通面粉 （和栗米粉一起过筛）

     2汤匙 栗米粉

     3粒 蛋黄 （大约55克）

     40克 细糖

     60毫升 牛奶

     1/2汤匙 柠檬汁

     100克 紫薯，压烂

     60克 紫薯，切成小丁状

     50克 菜油

      

     蛋白霜

     4粒 蛋白

     1/2茶匙 塔塔粉

     45克 细糖

    做法：

• 预热烤箱致摄氏165度。面粉和栗米粉一起过筛到一个碗里，备用。番薯洗净去皮切块。以大火蒸约15分钟致软，拿出100克的紫薯和牛奶一起搅打成泥。剩余的紫薯切成小丁状，备用。
• 蛋黄和细糖混合均匀。加入紫薯泥及柠檬汁，搅匀后，加入菜油，搅拌均匀。再筛粉类，搅拌均匀。
• 蛋白霜 – 用搅拌机把蛋白打致大起泡，细砂糖分3次加入，打致硬性发泡。
• 取出1/3蛋白霜与面糊翻拌均匀，再倒入剩余的蛋白霜，用刮刀轻轻翻拌均匀。
• 将一半的面糊倒入戚风烤盘，撒上紫薯丁，再把剩余的蛋白霜倒入。然后轻轻把气泡敲出。
• 把烤模放进烤箱倒数第二层，烤约50分钟。
• 蛋糕出炉后，即倒扣,完全待凉后脱模。