Wash the currants and remove them from the panicles with a fork. Heat 100 g jam while stirring. Remove from the heat and let it cool down briefly. Add the berries.
Grease a springform pan (26 cm Ø). Preheat the oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Cream 250 g butter, sugar, vanilla sugar and 1 pinch of salt with the whisks of the mixer.
Stir in the eggs one by one. Mix flour with baking powder and stir in quickly.
Put the dough and berry jam alternately into the mould. Pull through with a fork so that the dough and berry jam mix in streaks. Brush smooth and bake in a hot oven for 35-40 minutes (test with a chopstick!).
Take it out and let it cool down on a cake rack.
Stir the rest of the jam until smooth. Whip cream until stiff. Carefully fold in the jam. Dust the cake with icing sugar. Add the cream.