Drain the soy yogurt in a sieve lined with a cloth for 12 hours. This gives you a quark substitute.
Knead a shortcrust pastry from the ingredients for the dough. Grease a 26 mm springform pan and roll out 2/3 of the dough for the base and place in the pan. Shape the rest of the dough into finger-thick rolls and use them to pull up an edge in the mold approx. 4 cm.
Melt the margarine for the filling. Mix the starch with the sugar, stir in the quark substitute and add the remaining ingredients, except for the berries, and stir.
Pour the filling into the mold and distribute the blueberries evenly on top and press in lightly. If the edge of the dough is now significantly higher than the filling, then please press the edge down a little.
Bake the cake at 170 ° C hot air for about 60 minutes. Let cool down completely and then enjoy.