Wash the berries and scrape them off the panicles with a fork. Cream 200 g butter, vanilla sugar, sugar and salt with the whisk of the hand mixer. Stir in the eggs one by one.
Mix flour and baking powder and stir in alternately with the liqueur. Pour the dough into a greased springform pan (26 cm Ø) sprinkled with flour, spread the berries on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 50-55 minutes (stick test).
About 10 minutes before the end of the baking time, beat the egg whites until stiff, adding 100 g of sugar. Pour the beaten egg whites into a piping bag with a small star-shaped spout. Take out the cake and spray small tuffs onto the cake close together.
Bake the cake under the preheated grill of the oven (or electric oven: 225° C) for 2-3 minutes until light brown. Remove the cake from the oven and let it cool down.