In a large skillet over medium heat saute the finely chopped onions, carrot, and celery with the 2 tablespoons of butter or margarine. Add the beef and pork and cook until brown. Add chopped tomatoes, dried oregano, tarragon, sage, rosemary, and bay leaves. Add salt and pepper to taste. Simmer for an hour.
Near completion of cooking time add in mushrooms and simmer until softened, about 10 minutes.
