Dough: mix flour with baking powder. Mix the quark, oil, salt and egg together. Stir in half of the flour and knead in the remaining flour. Let rest for 30 minutes.
Topping: Chop the onions and fry them in a pan with the bacon. Mix the quark, eggs and cream with the spices (add seasoning to taste). Mix in the bacon / onion mixture and cheese.
Grease the baking sheet or line it with parchment paper. Roll out the dough and place on the tray. Brush with the bacon / quark mixture (leave the small edge free). Bake at 180 degrees (electric stove / top / bottom heat) for about 45 minutes.