Meringue: Egg whites 175g
Caster sugar 50g
Lemon juice 3g
Milk 55g
Egg yolk 85g
Purple sweet potato powder 15-20g
Ingredient Preparation
Egg yolk batter: Heat corn oil to 40-50% doneness, turn off heat when it feels hot to the palm, pour in flour and stir quickly until smooth, then quickly pour in milk.
Remove from heat and place over cold water to cool, pour into egg yolks, add purple sweet potato powder, and mix in a Z-shaped motion.
Meringue: Egg whites (use refrigerated eggs), lemon to remove odor, sugar to increase fluffiness. Beat egg whites until bubbly, add caster sugar, then add lemon juice. Scrape sugar from the sides with a spatula, beat with an electric mixer in large motions, counterclockwise in one direction. Do not change direction midway or the foam will deflate.
Whip the egg whites until the meringue forms stiff peaks; it is ready when it does not fall when inverted.
Add one-third of the meringue first, then incorporate the remaining meringue into the egg yolk batter in three additions, folding gently until evenly combined. Do not stir; follow the folding motion shown. Pour the batter into the mold. Spread evenly, then tap the mold twice to remove air bubbles. Place it on a baking tray. Preheat the oven for 5 to 10 minutes in advance (the shape may collapse if not preheated). Bake at 150°C with both upper and lower heat for 15 minutes, then bake at 160°C with both upper and lower heat for another 15 minutes to develop color (check the color after about 10 minutes; place the rack on the second level from the bottom). Drop the mold twice. Remove and let cool. Nestle multi-purpose light cream, 20 g sugar, 3 g lemon juice.Spread evenly.
Roll it up, wrap with plastic wrap, and place in the freezer. Plate and serve. Lemon fixes the color, and purple sweet potato powder produces a deeper color: add lemon juice to the purple sweet potato powder, then add oil and stir.
