The filling consists of a German buttercream, which is fundamentally different from its American version - the German variety is less stiff but wonderfully light and fluffy. Just try it and tell me what you think! ;-)
This is my mom's recipe and I just love it!
The recipe will serve about 9 people. I used a 8inch x 8 inch square baking frame/pan.
For the sponge you will need:
- 125 g (about 1/2 cup) butter at room temperature
- 100 g (about 1/2 cup) sugar
- 2 tbsp vanilla sugar
- 1 pinch of salt
- 2 eggs
- 180 g (about 1 1/3 cup) flour
- 2 tbsp baking powder
- 2 tbsp unsweetened cocoa powder
- 1 tbsp milk
- about 300 g (2 cups) sour cherries
- 2 tbsp flour
For the German buttercream you will need:
Very important: All ingredients for the buttercream need to be at room temperature or else the mixture will clot. Best store all of them in one place over night. You might also want to consider preparing the custard the day before so it can cool down to room temperature.
- 1/2 package of vanilla pudding powder
- 50 g (1/4 cup) sugar
- 250 ml (1 cup) milk
- 125 g (1/2 cup) butter at room temperature
For the chocolate frosting you will need:
- 150g (5.3 oz) dark chocolate
- 50 g (1.7 oz) white chocolate
- 1 1/2 tbsp coconut or any other neutral oil
1. Drain the cherries really well; possibly you might want to carefully dap them with a paper towel. Preheat your oven to 330 F (170 C) and grease a 8 x 8 inch baking sheet and cover with baking paper.
2. For the batter cream butter in a big bowl. Add sugar, vanilla sugar and salt. Add the eggs one at a time, beating well after each addition. In a seperate bowl combine flour and baking powder and sift into the egg mixture in two batches. Beat until you have a smooth batter.
3. Pour 2/3 of the batter into your prepared baking pan and smoothen the surface. Add the cocoa powder and one tablespoon of milk to the remaining third of the batter. Dust the drained cherries with 2 tablespoons of flour to prevent their sagging in the batter. Add to the dark batter and pour over the light batter and again smoothen the surface. Bake at 170°C / 330 F for about 40 minutes.
4. For the buttercream prepare the pudding according to the package's instruction, using pudding powder, sugar and milk (You might want to prepare it a day ahead; see tip above). Let cool completely, occasionally stirring it.
5. Cream the butter for the buttercream with a hand mixer. While mixing add the pudding a spoonful at a time. (Tip: in case the mixture clots just whip over a medium-warm water bath.)
6. Spread the buttercream evenly onto the sponge, smoothen the surface and let cool for about 1 hour.
7. For the chocolate frosting, melt the white and dark chocolate in seperate bowls (use a water bath or the microwave). Add 1/2 teaspoonful of coconut oil to the white chocolate and 1 teaspoonful of coconut oil to the dark chocolate. Spread the dark chocolate evenly on the buttercream-topped sponge. Using an icing bag, from the top to the bottom of the cake, pipe parallel lines of white chocolate onto the dark chocolate while it is still molten. Now, using a cake decorating comb, carve long waves from the left to the right ( at a aquare angle to the white lines) into the chocolate frosting, thus creating the Danube's waves with little white crests. Cut into equal sqares.