1. Preheat the oven to 375°F (190°C). Line two baking sheets with baking parchment and set aside.

2. Add flour, sugar, and butter for the streusels to a bowl and mix until you get different-sized streusels. Place in the fridge until ready to use.

3. For the dough, mix quark, oil, egg, and sugar in a large bowl until well combined. Mix the flour with baking powder, and salt and add to the bowl – mix in and knead until you get a nice and smooth dough. Divide into 8 equal portions, shape them into balls, and then pull/stretch each ball into a round disc with a diameter of about 6 inches (15 cm). The sides of the discs should be a bit thicker than the center. Place the discs on the baking sheets, spacing them slightly apart. Spread rice pudding on each disc (leaving the edges bare) and press some blackberries into the rice pudding. Sprinkle with a mix of cinnamon and sugar. Brush the edges with milk and sprinkle the streusels on top.

4. Bake the pastries for about 20 minutes. The edges should be browned nicely. You can bake one baking sheet after another or both at the same time. If you choose to bake everything at once you should switch the positions of the baking sheets halfway through the baking time so the pastries bake evenly. Remove the baked streusel taler from the oven and let cool down completely on a wire rack.