Devil’s Food Cake With Black Pepper Buttercream

Preparation

1. Step 1

   Make the cake: Heat oven to 350 degrees. Grease 3 8-inch round baking pans, line the bottoms of each with a round of parchment paper and grease the paper. Use a little cocoa powder to coat the insides of the pans, rotating pans so the cocoa comes up the sides, then tap out excess.

2. Step 2

   In a small bowl, whisk together cocoa powder and ⅔ cup boiling water. Whisk in milk. In a separate bowl, whisk together cake flour, baking soda, baking powder and salt.

3. Step 3

   In a large mixing bowl fitted with the paddle attachment, beat butter and sugar until fluffy. Beat in eggs 1 at a time, until incorporated. Beat in vanilla. With the mixer running on low speed, beat in a third of the dry ingredients, followed by half the cocoa mixture. Add remaining portions, alternating between two mixtures. Beat until smooth.

4. Step 4

   Divide batter evenly among prepared pans. Bake until the centers of the cakes are firm to the touch, 30 to 40 minutes. Cool cakes in their pans on a wire rack for 10 minutes; turn them out onto the rack to cool completely. (Peel off parchment paper if it sticks to the cakes.)

5. Step 5

   Make the buttercream: Fill a medium pot halfway with water (or use a double-boiler) and bring to a simmer. In a heatproof bowl that fits over pot, whisk together egg whites, sugar and salt. Cook, whisking constantly, until the sugar dissolves and mixture reaches 140 degrees on a candy or instant-read thermometer, about 5 minutes.

6. Step 6

   Using an electric mixer, whip until completely cooled and thick, about 5 minutes. Beat in butter a little at a time, until the frosting is smooth and spreadable. Beat in vanilla bean seeds and pepper.

7. Step 7

   Using a serrated knife, slice each cake in half horizontally. Place one bottom layer on a large platter or cake stand. Top evenly with a thin layer of buttercream. Repeat, alternating between cake and frosting, ending with a layer of cake. Cover cake loosely with plastic wrap and refrigerate while you prepare fudge frosting. (Cake can rest in the refrigerator for up to 1 day.)

8. Step 8

   Make the frosting: In a medium saucepan over medium heat, combine sugar, heavy cream and salt. Simmer, stirring occasionally, until sugar completely dissolves, about 5 minutes. Scrape mixture into a bowl. Stir in chocolate, butter and vanilla until smooth. Set bowl over a larger bowl filled with ice. Use a hand mixer or an immersion blender with the whisk attachment to whip until mixture is thick and cool, about 5 minutes. Spread frosting over the top and sides of the cake.