Donauwelle | German Chocolate Cherry Cake

In a large bowl, whisk together egg yolks, cornstarch, flour, and sugar until smooth. This may be hard to mix at first, but if you continue whisking, the mixture will become light, fluffy, and pourable.

Heat the milk on the stove over medium heat just until little bubbles form around the edges. You don’t want to let this boil or it will form a skin.

Slowly drizzle about half of the hot milk into the egg mixture as you whisk. This is called tempering the eggs. Return the mixture to the saucepan and cook over medium heat, stirring constantly until it forms the consistency of a pudding. Once it bubbles and burps, continue cooking and whisking for 2 more minutes.

Remove from heat and cover the surface directly with plastic wrap to prevent a skin. Let it cool completely to room temperature. Putting it in the fridge for 45 minutes to 1 hour can help accelerate the cooling.

Preheat oven to 180°C (350°F). Grease and line a large rectangular cake pan (approx. 14×18 in / 35×46 cm).

In a mixer, beat butter, sugar, vanilla sugar, and salt until light and fluffy.

Add eggs one at a time, beating well after each addition.

Stir in flour and baking powder until just combined.

Spread half of the batter evenly into the bottom of the prepared pan, smoothing it to the edges.

To the remaining batter, add cocoa powder and milk. Mix to combine.

Gently spread the chocolate batter over the vanilla layer.

Arrange drained cherries in rows across the top, pressing them slightly into the batter.

Bake at 350°F (180°C) for 30–35 minutes, or until a toothpick inserted in the center comes out clean.

Let the cake cool completely in the pan.

Once the pastry cream is at room temperature, beat the softened butter until pale and fluffy.

Slowly add the room temperature pastry cream to the butter, a spoonful at a time, beating until smooth and spreadable.

Spread the buttercream evenly over the cooled sponge cake.

Chill the cake for at least 1 hour to allow the buttercream to firm up.

Melt chocolate with vegetable oil in a double boiler or heatproof bowl over simmering water, stirring until smooth.

Pour the warm glaze over the chilled buttercream and gently spread it evenly.

Use the tines of a fork to draw wave patterns across the surface of the chocolate.

Chill the cake for 1–2 hours until the glaze is set.

For best flavor and texture, let it sit overnight in the fridge. The buttercream softens the sponge and creates that perfect, cohesive bite.