2 tbsp. butter
2 lg. onions, sliced
1/2 c. diced celery
1/2 c. diced green pepper
1 tsp. minced garlic
1 lb. ground beef
1/2 lb. mushrooms, sliced
1 (15 oz.) can tomato sauce
1 tsp. salt
1/2 tsp. pepper
2 c. cooked macaroni
8 oz. cheddar cheese, shredded

Preheat oven to 350 degrees. Melt butter in large skillet over medium high heat. Add mushrooms, onions, green pepper, celery, and garlic. Cook, stirring, until vegetables are softened, about 10 minutes. Add beef and cook until it loses its pink color. Stir in tomato sauce, salt, and pepper. Bring to a simmer. Stir in cooked macaroni, then cheese. Spoon into 13 x 9 inch baking pan. Bake uncovered 30 minutes.