There’s a certain amount of discussion about when to use natural vs Dutch-process cocoa powder, which I explain in my chocolate book, if you’re interested in the details, but I’ve made this cake with both kinds of cocoa powder and no one’s refused a slice cake made with either. I make the frosting with water, since I think the cake is plenty rich as it is. But if you want a creamier frosting, using cream in place of the water.
