Sauté the veal and onion until brown, seasoning with garlic powder. Slice eggplant thin and layer on bottom of casserole dish. Next layer is meat and onion, then green pepper and mushrooms. Season with oregano, salt, pepper and garlic powder. Then add can of tomatoes. Bake covered for 1 hour at 350ºF. Remove cover and bake another 15 minutes. Serves 4 to 6.