Let the blueberries thaw for about 30 minutes. Cream fat, vanilla sugar and sugar with the whisk of the hand mixer. Stir in eggs one after the other. Mix flour and baking powder and stir in alternately with the yoghurt. Finally stir in blueberries. Pour the dough into a greased, flour-dusted ring cake mould (2.5 litres capacity; 22 cm Ø). Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 50 minutes (test with sticks)
Take the cake out of the oven. After about 10 minutes, carefully turn out of the tin and let it cool down on a cake rack
Waiting time approx. 30 minutes