This recipe is for a fluffy and moist chocolate-flavored Taiwanese castella cake that can be made without using any oil. The oil content of the chocolate and heavy cream replaces that of vegetable oil, resulting in a moist texture. The batter is made by sifting together cake flour and cocoa powder, then mixing in warmed heavy cream, milk chocolate, and egg yolks. The brown sugar is added all at once and mixed with meringue, and then baked slowly in a water bath. This results in an exquisite chocolate Taiwanese castella cake with a fine texture and elasticity that is less prone to cracking on the surface. The recipe includes detailed explanations of how to whip the meringue, mix the dry ingredients, and bake, making it a recipe that is hard to fail at.