Mix flour and baking powder. Add curd, oil, milk and salt. Mix with the dough hook of the mixer until smooth.
For the topping, sauté onion rings in hot fat until translucent. Season with pepper and caraway seeds.
Grate bacon cubes and cheese.
Roll out dough on a greased baking sheet. Spread cooled onions and bacon on dough. Sprinkle cheese on top. Mix egg and whipped cream, season with salt and pepper and pour over the top.
Place in oven and bake at 200 degrees for 20 to 30 minutes.
Serve the onion tart warm.