Käsesahnetorte (German Yogurt Mousse Cake)
Originally made with quark, the traditional German cake known as kasesahnetorte can now be made with Greek yogurt, which is much more widely available in the United States.
Preheat the oven to 400 degrees F (200 degrees C).
Place a large piece of parchment paper over the bottom of a 9-inch springform pan.
Make sure it is taught then clip on the rim and cut off the excess parchment paper.
Grease the sides.
Beat egg yolks warm water and sugar for sponge base in a bowl with an electric mixer until pale and fluffy.
Mix in vanilla extract.
Mix cake flour and baking powder together in a separate bowl.
Sift over egg yolk mixture and fold in thoroughly until no lumps remain.