Knead the first six ingredients (mix the flour and baking powder beforehand). Roll out on a floured work surface and knock out a tart pan (23 cm x 23 cm) with it. Form a border about 3 cm high.
Mix the remaining ingredients without the berries and powdered sugar. Carefully fold in 400 g of berries. Distribute evenly on the dough base.
Bake in a preheated oven at 175 ° C for about 40 minutes.
After cooling, cover with the rest of the berries and sprinkle with powdered sugar.
Of course you can also take a round shape and only one type of currant.