Triple Chocolate Mousse Cakes Ingredients Dark Chocolate Cake Unsalted butter, softened, to grease Unsweetened cocoa powder, for dusting 83 g (2/3 cup) plain (all-purpose) flour 39 g (1/3 cup) unsweetened Dutch-process cocoa powder ½ teaspoon baking soda ¾ teaspoon baking powder ¼ teaspoon salt 150 g (2/3 cup) caster (superfine granules) sugar 1 large