1 onion, minced
½ cup celery, chopped
4 tbsp. butter
1 tbsp. flour
½ cup milk
2 cup leftover roast beef, cubed
3 cup cooked spaghetti
1 small can mushrooms
1 cup tomato sauce
1 tsp. Worcestershire sauce
grated cheese

Saute onion and celery in butter in skillet until tender. Blend in flour. Stir in milk. Cook until thick stirring constantly. Add remaining ingredients except cheese. Pour into casserole. Top with remaining cheese. Bake at 350 degrees for 25 minutes.