Rhubarb, Currant, and Walnut Tart
Preheat the oven to 180°C (approximately 350°F). Brush the tart pan with butter.
Roll out the puff pastry to a round slightly larger than the tart tin and cut the edge into a decorative zig-zag pattern. Transfer to the tart tin.
To make the filling: Stir together the quark with the almonds, 1 tablespoon starch, sugar, vanilla sugar, and eggs. Spread this evenly over the dough. Rinse the rhubarb, trim, and cut into pieces. Mix the remaining cornstarch with the rhubarb and scatter evenly over the filling. Rinse the currants, remove the stems, and spread the currants and walnuts evenly over the tart.
Bake about 40 minutes, until golden brown.
Remove from oven and let cool. Serve dusted with powdered sugar.