The icing on this coffee-infused cake starts out light and becomes deepest in color and flavor at the bottom. The meringue drops, tinted with cocoa and coffee extract, are dipped in chocolate, then set on the tiers.
Preheat oven to at 350 degrees. Coat cake pans with cooking spray; cover bottoms with parchment, and coat again. Set aside. Whisk cocoa powder into coffee in a large bowl until cocoa has dissolved; set aside.
Sift together flour, baking soda, and baking powder in a large bowl; set aside.
Put butter and sugar into the bowl of an electric mixer fitted with the paddle attachment; mix on medium-high speed until pale and fluffy. Add eggs, 1 at a time, mixing well after each addition. Mix in half of the flour mixture. Mix in coffee mixture. Mix in remaining flour mixture. Divide batter among prepared pans.
Bake until a cake tester inserted into centers comes out clean. Transfer to wire racks; let cool in pans slightly. Invert cakes onto racks. Remove parchment; reinvert. Cakes can be wrapped in plastic and stored at room temperature up to 1 day.
To assemble: Cut each cake horizontally into three 1-inch layers. Brush each layer with syrup (see note below for amounts). Spread ganache over 1 layer; top with another layer. Spread with dark-coffee buttercream. Top with remaining layer; spread with vanilla buttercream. Frost tier with buttercream (vanilla for top tier, light-coffee for middle, and dark-coffee for bottom). Decorate tiers with meringue drops.
Note: Batter amounts and cooking times are for 3-inch-deep round pans. 6-inch-diameter: 5 1/2 cups batter, 1 hour 20 minutes; 8-inch-diameter: 7 1/2 cups batter, 1 hour 30 minutes; 10-inch-diameter: 11 cups batter, 1 hour 30 minutes.
Filling and frosting amounts for each tier are as follows. 6-inch-diameter: 3 tablespoons syrup per layer (9 tablespoons total), 1 cup ganache, 1 cup dark-coffee buttercream, 3/4 cup vanilla buttercream for top layer, 11/2 cups vanilla buttercream for exterior; 8-inch-diameter: 1/4 cup syrup per layer (3/4 cup total), 1 3/4 cups ganache, 2 cups dark-coffee buttercream, 1 1/2 cups vanilla buttercream, 2 1/4 cups light-coffee buttercream for exterior; 10-inch-diameter: 1/2 cup syrup per layer (1 1/2 cups total), 2 1/2 cups ganache, 3 cups dark coffee buttercream for layer, 2 1/2 cups vanilla buttercream, 3 cups dark-coffee buttercream for exterior.
Make this batter recipe 1 1/2 times for the 3-tiered cake. Bake 1 cake for each tier. The finished cake will serve about 70.