- Grease a 9x9x2-inch baking pan. Line the bottom of the pan with parchment or waxed paper; grease the paper. Flour the pan; set aside.
- In a medium bowl, stir together the flour, cocoa powder, salt, baking powder, and baking soda; set aside. In a small bowl, dissolve the coffee crystals in the hot water. Stir in the buttermilk or sour milk; set aside.
- In a large bowl, beat the 3/4 cup butter with an electric mixer on medium to high speed for 30 seconds. Add the granulated sugar and the vanilla; beat until combined. Add eggs, one at a time, beating well after each addition. Add the flour mixture and the buttermilk mixture alternately to the beaten mixture, beating after each addition just until combined. Spread the batter in the prepared pan.
- Bake in a 350 degree F oven about 35 minutes or until a wooden toothpick inserted near the center comes out clean. Cool in pan on a wire rack for 10 minutes. Remove from pan. Remove paper; cool completely.
- Meanwhile, for filling, in a small saucepan, bring the whipping cream and 1 tablespoon corn syrup just to boiling. Place milk chocolate in a small bowl; pour hot cream mixture over chocolate. Stir until smooth. Place the nuts and powdered sugar in a food processor bowl or blender container; cover and process or blend until finely ground. Stir into melted chocolate mixture. Set aside to cool.
- For glaze, in a small saucepan, heat and stir the semisweet chocolate, the 1/2 cup butter, and 1 tablespoon corn syrup over low heat until melted and smooth. Cool 30 minutes.
- To assemble, split the cake layer in half horizontally. Place bottom on a serving platter, cut side up. Spread with filling. Place remaining cake half on top of filling, cut side down. Spread glaze over top and sides of cake. Let stand at room temperature for 30 to 60 minutes or until glaze is set.
From the Test Kitchen
To make 1/2 cup sour milk, place 1-1/2 teaspoons lemon juice or vinegar in a glass measuring cup. Add enough milk to measure 1/2 cup total liquid; stir. Let the mixture stand for 5 minutes before using it.
To toast hazelnuts, spread in a single layer in a shallow baking pan. Bake in a 350 degree F oven for 10 to 15 minutes or until toasted, stirring occasionally. To remove hazelnut skins, place warm, toasted nuts on a clean kitchen towel. Fold the towel over the nuts and rub to remove the skins.
Nutrition Facts (Chocolate-Hazelnut Cake)
- Per serving:
- 420 kcal ,
- 28 g fat
- (13 g sat. fat ,
- 89 mg chol. ,
- 290 mg sodium ,
- 40 g carb. ,
- 2 g fiber ,
- 5 g pro.