Pound the cutlets thin and sprinkle them with flour on both sides, shaking off any excess. Place olive oil, salt pork and butter in a skillet; heat. Add onions and saute until medium brown. Add the veal and brown slowly for 3 minutes. Turn over, and cook for 2 minutes longer. Add salt, pepper and wine, cover, and simmer for 5 minutes.
Separate stems and caps of mushrooms. Chop the stems fine and cut the caps into thin slices. Discard cores and seeds from peppers and cut them into very thin slices. Add mushrooms, green peppers and tomatoes to the veal, cover, and cook for 5 minutes. Chop garlic and parsley together and stir the mixture into the sauce. Simmer, uncovered, for 10 minutes, or until done. Taste for salt. Drink Chianti with this.