How much frosting should I make? The listed recipe makes enough frosting to fill and frost a three layer cake. If you're only baking two layers, I recommend cutting the recipe down. Use the following increments: 1 cup softened butter, 1 pound powdered sugar, 1/2 cup cocoa powder, 1/3 teaspoon salt (or a scant 1/2 teaspoon), 1 teaspoon vanilla, 1/4 cup heavy cream (or more, as needed). Use the same directions to make the frosting as listed in the recipe card.