Heat 45ml of olive oil in a frying pan and fry the onion for 7 minutes until soft.
Add the garlic cloves, season with salt and pepper, and cook for one minute.
Stir in the chopped tomatoes and vegetable stock, then simmer for 40 minutes to reduce.
Flatten the veal escalopes with a meat mallet between cling film until 1cm thick.
Season and flour the veal, then sauté in the remaining oil for 3 minutes per side.
Pour the tomato sauce over the veal, top each with mozzarella, and simmer for 5 minutes.
Serve the dish immediately while hot.