For the compote, carefully wash the currants and remove the berries from the panicles with a fork. Stir pudding powder, 2 tablespoons sugar and 100 ml nectar until smooth. Bring 1⁄4 l nectar to the boil. Stir the pudding powder into the boiling nectar, bring to the boil and simmer for at least 1 minute.
Remove from heat, carefully stir in the berries and allow to cool.
For the short pastry, mix 400 g flour, 150 g sugar, vanilla sugar and 1 pinch of salt. Add eggs and 250 g butter in pieces. Knead first with the dough hooks of the mixer, then with your hands to a smooth dough.
Grease half of a baking tray. Roll out one half of the dough rectangularly (approx. 32 x 20 cm) on a floured work surface. Place on the greased half of the baking tray and sprinkle with breadcrumbs.
Spread the berry compote on top, leaving a rim of about 1 cm all around.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Roll out the remaining dough into a rectangle (approx. 32 x 20 cm) and carefully place on the dough with compote. Press the edges of the dough well together.
Bake the cake in a hot oven on the lower shelf for 20-25 minutes.
For the icing, mix icing sugar and lemon juice until smooth. Take the cake out of the oven. Pour the icing over the still hot cake. Let it cool down on a cake rack. Whipped cream tastes good with it.