A good chocolate raspberry cake recipe is chocolate-raspberry layer cake from the Food Network, which blends raspberry puree into both the batter and the frosting of the cake. Some other good recipes include raspberry chocolate cake from Taste of Home, and white chocolate and raspberry cake from BBC.
To make the chocolate raspberry cake from the Food Network, first prepare the raspberry pure by blending a 12-ounce bag of frozen thawed, unsweetened raspberries. In one bowl, mix one box of chocolate cake mix minus one tablespoon with 1 cup of raspberry puree, 1/2 cup of vegetable oil, 3 eggs and 1/4 cup of water. In another bowl, stir 1 1/2 cups of semisweet chocolate chips with the remaining 1 tablespoon of cake mix. Fold the chocolate chips into the cake batter, and pour into two round nonstick baking pans. Bake at 325 degrees Fahrenheit for 30 to 35 minutes.
As the cake bakes and cools, beat together 1 1/2 cups of powdered sugar, 1 cup of unsweetened cocoa powder, 1 cup of softened unsalted butter, 1/2 cp of cream cheese and 1/3 cup of sour cream to make the frosting. In a separate bowl, mix together 3/4 cup of the frosting and the rest of the raspberry puree. Frost the top of one of the round cakes with the raspberry frosting, place the other round cake on top, and frost the entire cake with the rest of the chocolate frosting. Garnish with chocolate curls and fresh raspberries.