Rum-Mocha Walnut Layer Cake
Ingredients
Cake
2 tablespoons Fine dry bread crumbs (for dusting)
2 cups walnut halves (about 7 ounces)
¼ cup unsweetened cocoa powder (not Dutch process)
½ cup cake flour
1 teaspoon instant espresso powder
8 large eggs (separated)
1 cup sugar
2 teaspoons pure vanilla extract
¼ teaspoon salt
Filling
6 large egg yolks
½ cup sugar
1 pinch of salt
2 tablespoons instant espresso powder dissolved in 1/ cup hot water
1 pound unsalted butter (softened)
3 tablespoons coffee liqueur
1 tablespoon pure vanilla extract
½ cup dark rum (for brushing)
1 ½ cups finely chopped walnuts (about 5 ounces plus walnut halves for garnish)
Directions
Preheat the oven to 350°. Butter two 9-inch round cake pans and line the bottoms with parchment paper. Butter the parchment and dust with bread crumbs, tapping out any excess. In a food processor, pulse the walnuts until finely chopped. Add the cocoa powder, cake flour and espresso powder and pulse until the walnuts are finely ground. Transfer to a bowl.
In a large bowl, using an electric mixer, beat the yolks at medium speed until thick and pale, 3 minutes. Beat in 2/3 cup of the sugar; increase the speed to high and beat until thick, about 5 minutes. Beat in the vanilla. In a medium bowl, using clean beaters, beat the egg whites and salt at medium