Peel and finely chop the onion and garlic. Clean, wash and roughly cut the mushrooms. Heat the oil. Fry onion, garlic, mushrooms and minced meat for about 5 minutes, turning them over.
Season with salt, pepper, paprika and oregano. Roll out the pizza dough on a floured work surface to form a rectangle (approx. 33 x 40 cm) and place in a greased casserole dish (approx. 25 x 32 x 5 cm).
Press the edge up at the sides. Sprinkle with breadcrumbs. Spread the minced meat mixture on top. Clean, wash and slice the tomatoes and place them on the minced meat. Drain the mozzarella, cut into slices and spread on the tomatoes.
Bake the tomato mince cake in a preheated oven (electric range: 200 ° C/ gas: level 3) for about 30 minutes. Remove the minced cake and cut into pieces. Serve sprinkled with oregano leaves. Results in about 8 pieces.