• Place the cleaned and finely chopped rhubarb on a sieve, wash and drain. Grease a baking sheet and dust with flour. Place a baking frame (30 x 28 cm) on top. Preheat the oven to 180 degrees or fan-assisted: 160 degrees.

For the crumble dough:

• Mix the flour with baking powder in a mixing bowl. Add the melted butter, sugar and egg and use the dough hook of the hand mixer to make crumbles. Spread about 2/3 of the crumble evenly in the baking frame and press firmly with a tablespoon. Bake for about 15 minutes on the middle shelf. Take out and let cool down a bit. Reduce the oven temperature to 170 ° degrees (top / bottom heat) or circulating air: 150 ° degrees.

For the curd mass:

• Put the quark with sugar, pudding powder, eggs and grated lemon zest in a mixing bowl and mix with the mixer (hand mixer). Spread the mixture on the pre-baked base.
• Mix the drained rhubarb well with 2 tablespoons of sugar and a little cinnamon and spread over the curd mixture. Sprinkle the remaining crumble on the rhubarb topping and press lightly. Bake the cake on reduced heat in the lower third of the oven in about 55 minutes.
• Remove the finished cake, place it with the baking sheet on a wire rack and let it cool down. Carefully detach the baking frame from the edge.
• Before serving, dust the cake with powdered sugar and cut into pieces. Whipped vanilla cream tastes good with it.