Step by step

Whisk the egg yolks with 4 tablespoons of warm water, then add the sugar.

Tips
In the Black Forest region, in the south of Germany, this cake is called Schwarzwälder Kirschtorte. Freiburg is widely known for the  famous black forest cake and for being the home of cuckoo clocks.
Trivia
When cherries are in season, you can replace the candied ones with the fresh ones.