Quickly knead all the ingredients for the dough together. Wrap in foil and refrigerate for approx. 30 minutes.
Line a tart pan (28 cm) with baking paper and preheat the oven to 200 degrees top / bottom heat (convection: 180 degrees).
Roll out the dough thinly on a floured work surface, line the mold with it and form an edge. Prick the base several times with a fork and prebake for about 10 minutes. Remove and lower the temperature to 150 degrees.
Wash and dry the currants and pull them off the panicles. Cut open the vanilla pod and mix the pulp with sour cream, mascarpone, eggs and sugar. Spread on the cooled tart base and sprinkle with the currants. Bake ready in approx. 35 minutes.