Dutch-Chocolate Angel Cake
The secret to a perfect angel food cake lies in beating the egg whites and then stabilizing them with cream of tartar. Dutch-process cocoa has nothing to do with the Netherlands but refers to a process in which the cocoa is "dutched," or alkalized, resulting in a more mellow and full-bodied cocoa. Though the regular variety can be used, Dutch-process cocoa gives the sauce a subtle richness. Use an ungreased tube pan so the egg whites in the batter will cling to the sides and "climb" as the cake bakes.