Stir cream quark with egg yolks, powdered sugar and cornstarch. Season with rum, grated lemon zest and vanilla sugar.
Beat egg whites with sugar until stiff and fold into curd mixture. Butter a soup plate and pour in the curd mixture.
Boil up some white wine with sugar and vanilla sugar, add rhubarb pieces and let cool down in the stock. Place the rhubarb pieces on the curd mixture and garnish the spaces in between with halved strawberries.
Bake in the oven at 250 °C for 10 minutes until golden brown. Dust with powdered sugar and serve with ice cream.