In large pan bring tomatoes to boil. Reduce heat. Add 2 tablespoons cornstarch mixed with 1/2 cup water to thicken. Add tomato sauce. Let simmer. In another pan saute onions, peppers and mushrooms in 1 tablespoon butter. Add ground beef and brown. Drain mixture well. To tomato sauce mixture add mix and spices. Add ground beef, peppers, onions and mushrooms. Let sauce simmer until flavors blend. Best if simmered 2 hours or more.