• Butter for greasing pans
• 2 cups all-purpose flour , plus extra for dusting
• 3/4 cup unsweetened cocoa powder
• 1 teaspoon instant espresso powder
• 1 1/2 cups boiling water
• 1 cup granulated sugar
• 3/4 cup packed brown sugar
• 1 1/2 teaspoons baking powder
• 1 1/2 teaspoons baking soda
• 1/2 teaspoon salt
• 1 stick (8 tablespoons) unsalted butter , melted
• 2 large eggs
• 1 teaspoon vanilla extract

• 2 sticks (16 tablespoons) unsalted butter , softened
• 2 cups confectioners' sugar
• 1 tablespoon vanilla extract
• 6 ounces good-quality unsweetened chocolate , melted and cooled

To make cake: Preheat oven to 350°. Grease two 8" x 2" round cake pans with butter. Line bottoms with parchment or waxed paper. Grease the paper, and dust pans with flour.

In a small bowl, add cocoa and espresso powder. Add boiling water; whisk until smooth.

In a large bowl, stir remaining 2 cups flour, granulated sugar, brown sugar, baking powder, baking soda and salt until blended. Add melted butter, eggs, vanilla and hot cocoa mixture to dry ingredients. With an electric mixer on low, beat until dry ingredients are moistened. Increase to medium and beat 2 more minutes. Pour batter into prepared pans. Bake 30 to 35 minutes, until an inserted toothpick comes out clean. Cool on wire racks 10 minutes. Run a knife around sides and invert cakes onto racks. Turn topsides up and cool.

To make frosting: In a large bowl, beat butter, sugar and vanilla with an electric mixer on low until blended. Shift to medium; beat until smooth and fluffy, about 2 minutes, scraping bowl as needed. Add chocolate; beat until well blended and fluffy.

Peel paper off cake layers. Place one layer, rounded side down, on a plate. Spread with 1 cup frosting. Top with second cake layer, rounded side up. Frost top and sides with remaining frosting.