Wash the schnitzel and dab dry. Heat oil in a pan. Fry the escalopes on each side for about 2 minutes. Remove and season with salt and pepper. Wash and clean the tomatoes and cut them into large pieces.
Wash the basil, dab dry and chop finely, except for a little to garnish. Peel and chop the onions. Tomatoes and onions briefly in the frying fat, stir in basil, season with salt and pepper.
Layer the meat and tomatoes with the onions in a greased casserole dish. Drain the mozzarella and cut into cubes, spread over the casserole. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes.
Garnish with basil. Herb baguette tastes good with it.