Butter, sugar, vanilla sugar, rum, lemon juice and grated lemon zest
stir until frothy. Gradually stir in egg yolks and continue to beat until frothy.
Mix the flour, baking powder, vanilla pudding powder and semolina and stir alternately with the quark and cream into the yolk mixture. Fold in the egg whites.
Turn the diced strawberries in flour and stir into the batter.
Pour the dough into a greased, floured Gugelhupf pan and bake in the preheated oven at 175 degrees for about 60 minutes.
Cover the cake with foil at ¾ the baking time.
Let cool, sprinkle with powdered sugar and coconut flakes and top with halved strawberries.