Preheat the oven to 375 degrees F.

Butter and line a 9-inch round cake pan with parchment paper, then butter the parchment paper and set aside.

Whisk egg yolks, whole eggs, and sugar in a large metal bowl over simmering water until the mixture reaches 120 degrees F.

Remove from heat and whisk until thick and fluffy, about 10 minutes.

Gently fold in sifted all-purpose flour, wheat flour, and cocoa powder.

Pour the mixture into the prepared cake pan and flatten with a rubber spatula.

Bake for about 20 minutes, or until a toothpick inserted into the center comes out cleanly.

Invert the cake onto a wire rack and cut vents in the parchment paper.

Let the inverted cake rest for 24 hours.

Combine 2 tablespoons Kirsch, 1 1/2 tablespoons sugar, corn flour, lemon zest, and cinnamon in a small bowl.

Bring the remaining 4 tablespoons Kirsch to a boil in a small saucepan.

Reduce heat to medium, add the sugar mixture, and stir.

Add the drained cherries, stir, and heat through.

Remove from heat, pour into a bowl, and let cool.

Cut the cake into 3 layers.

Spread melted chocolate evenly over the bottom layer, and refrigerate to cool and harden slightly.

Whip heavy cream with remaining 2 tablespoons sugar and vanilla sugar until light and airy.

Combine water and sugar in a small saucepan.

Bring to a boil, stirring constantly, until sugar has dissolved.

Remove from heat and add Kirsch; stir to combine.

Remove the chocolate-covered base layer from the refrigerator and brush with syrup.

Add about 1/2 of the cherry filling mixture and 1/4 of the whipped cream.

Repeat the layer, brushing with syrup, then filling, and then whipped cream.

Place the third cake layer on top, brush with syrup, and cover with whipped cream.

Spread the remaining whipped cream around the side of the cake.

Decorate the top of the cake with chocolate shavings and additional cherries.