Danube Waves Cake

Beat the eggs and sugar together for 3–5 minutes.

Add the vegetable oil and milk, and beat briefly to combine.

Add the flour mixed with the baking powder and beat just until the flour is incorporated — don't overmix.

Transfer about half of the batter to a separate bowl, add the cocoa and 2 tbsp of milk, and beat briefly until the cocoa is evenly distributed.

Lightly grease the pan (mine is 25 x 25 cm) and pour in the light batter.

Pour the dark batter evenly over the top and smooth it out if needed.

Peel the apples, remove the cores, cut into pieces, arrange them over the batter, and press them in with your fingers. Instead of apples, you can use fresh or frozen cherries, strawberries, or other large berries (do not thaw frozen berries beforehand).

Bake the cake in an oven preheated to 180°C (350°F) for about 20–30 minutes, or until a toothpick comes out clean — but don't overbake; don't dry out the cake! Let the finished cake cool completely.

Combine all of the custard cream ingredients except the butter in a heavy-bottomed saucepan and whisk well until the flour is evenly dissolved (flour disperses beautifully in cold milk).

Cook over medium heat, whisking constantly, until the mixture thickens considerably (the cream should be very thick). Let the finished cream cool completely — completely!

Beat the softened butter briefly.

Add the cooled custard mixture in two or three additions, beating well after each addition.

This is what the finished cream looks like.

Spread the cream over the cake layer and smooth it out.

Make the ganache. Break the chocolate into pieces and place in a bowl. Heat the heavy cream and butter until very hot (the butter should melt, but the mixture should not boil). Pour the hot cream over the chocolate and immediately start stirring vigorously. It may look uneven at first, but keep stirring until the mixture is completely smooth, glossy, thick, and shiny. If the ganache turns out too thin, refrigerate it briefly to let it firm up.

Pour the ganache evenly over the cream. I used a spatula to create a wave pattern on top, so the waves appear not only inside the cake but on the outside too :)

Refrigerate the cake for at least a couple of hours to allow the cream and ganache to set. Done.

Slice and serve. The Danube Waves Cake has an incredibly soft and tender sponge, the most delicious custard cream, and a gorgeous chocolate ganache to top it all off! Absolutely wonderful!