Japanese Cotton Sponge Cake Recipe. In a separate bowl whisk the egg whites and cream of tartar till they are foamy. Over a double boiler placing the bowl over a pot with simmering water on low heat whisk the egg mixture until it becomes lukewarm until the sugar dissolves.
Over a double boiler placing the bowl over a pot with simmering water on low heat whisk the egg mixture until it becomes lukewarm until the sugar dissolves. Add in sugar and salt in batches and continue to whip till the egg whites are smooth and glossy close to stiff peaks. Pour the sponge cake mix on the dough after it doubles in size.
Bake as the same temperature and duration in the sponge cake recipe.
Pour the sponge cake mix on the dough after it doubles in size. In a separate bowl whisk the egg whites and cream of tartar till they are foamy. When you lift the batter up the tips should stand with little crooks at the end of the tips. Pour the egg yolk mixture into the egg whites and fold to mix i used my bare hand until you do not see any streaks.