Saute meat and onions together in oil (use large frying pan) until meat is brown and crumbly. Add tomatoes, tomato sauce, tomato paste, green peppers, grated cheese, zucchini and olives. Add seasonings. Simmer 10 minutes, turn into 8 x 12-inch baking dish and sprinkle generously with Parmesan cheese. Bake at 350 degrees for 1 hour or until sauce is thickened and top is nicely browned and slightly crusty.