I use LorAnn raspberry flavoring oil in the frosting to boost the berry flavor. I recommend using it if you can find it, but the cake is just as lovely with vanilla flavored frosting. If you prefer vanilla frosting, omit the flavoring oil and add 1 teaspoon pure vanilla extract.
Decorative square of chocolate or chocolate transfer*
Instructions
Preheat the oven to 350° F. Grease and flour an 8 x 8inch square cake pan.
Using an electric mixer beat the butter in a large bowl until smooth. Add the sugar and eggs; beat until lightened in color. Add the cocoa, baking soda, vanilla extract, and salt; mix well. Beat in the flour in 3 additions, alternating with the sour cream (begin and end with the flour). Add the hot coffee and mix until a smooth batter forms.
Pour the batter into the prepared pan. Bake until a toothpick tester comes out clean, approximately
40 to 50 minutes. Cool the cake in the pan for 10 minutes before inverting and cooling completely on a wire rack.
Level the top with a serrated knife, if needed. This cake usually doesn’t crown much (that means it doesn’t get the bump on top when it bakes) and I rarely have to level it.
Trace the bottom of the 8x8-inch square cake pan on a piece of parchment paper. Cut out the shape and fold in half diagonally. Conservatively trim away two corners with scissors to create a heart shape. Lay the paper heart on the cake and, holding a serrated knife vertically, cut the cake around the paper using gentle sawing motions. Save the extra cake pieces as ice cream crumbles, or have a few bites for a pick-me-up while you frost the cake.
For the frosting, combine the butter and confectioners’ sugar in a mixing bowl. Beat with an electric mixer until smooth and fluffy. Add the raspberry flavoring oil and a few drops of the liquid red food color. Beat until combined. Add red food color a little at a time until a red-raspberry color is achieved. Spread the frosting onto the cake with an off-set spatula. Make sure you get at least 1/4-inch thickness of icing on the sides of the cake, otherwise the berries will not stick!
Starting at the pointed end of the heart, line the raspberries around the bottom edge of the cake. Pack them together closely so as little of the frosting shows through as possible. Travel upward with your berry rows until the entire cake is covered in raspberries. If you see any icing lines showing through, dab a little frosting on a berry and place it over the exposed icing.
Use a little frosting to adhere the chocolate square in the upper left hand corner of the cake.
Store the cake in the refrigerator. Remove it about 1 hour before serving so that the cake loses its chill. Dust with powdered sugar and cut into slices. Store the leftovers in the refrigerator.