Best Chocolate Cake

Step 1:Position rack in center of oven and preheat to 350°F. Butter three 8-inch-diameter nonstick cake pans with 1 1/2-inch-high sides. Place devil\’s food cake mix, 1 cup water, 1/3 cup vegetable oil, eggs, vanilla extract and 1/4 cup sour cream in large bowl. Using electric mixer, beat batter 2 minutes. Stir in 1 cup semisweet chocolate chips.

Step 2:Divide batter among prepared pans (about 1 3/4 cups batter for each). Bake until tester inserted into center of cake layers comes out clean, about 25 minutes. Cool cake layers in pans on racks 15 minutes. Run small sharp knife between pan sides and cake layers to loosen. Turn out onto racks; cool completely. Bring 1/2 cup raspberry jam and 3 tablespoons unsalted butter to simmer in heavy large saucepan over medium heat, stirring often. Remove from heat. Add remaining 3 cups semisweet chocolate chips and stir until melted. Add remaining 3/4 cup sour cream and 2 cups powdered sugar. Using electric mixer, beat frosting in pan until smooth and thick, about 2 minutes.

Step 3:Place 1 cake layer on platter. Spread 3/4 cup frosting over. Top with second cake layer. Spread 3/4 cup frosting over. Top with third cake layer. Chill cake until frosting sets slightly, about 15 minutes. Spread remaining frosting in swirls over top and sides of cake. (Can be prepared 1 day ahead. Cover with cake dome and let stand at room temperature.)