Mix well the ingredients for the dough without flour and baking powder. Mix flour and baking powder and stir in briefly. Place the dough on a baking sheet lined with baking paper (dimensions approx. 20 x 25 cm) and smooth it out. Mix the ingredients for the filling well (it stays liquid). Put the filling on the dough very slowly and carefully so that it does not mix with the dough. Put everything in the oven and bake at 180 ° C for about 45 minutes.