Spaghetti Casserole

Ingredients

• 1 to 1 1/4 lb. ground beef
• 3 Tbsp. oil
• 2 medium onions, chopped
• 1 large green pepper, chopped
• 2 c. celery, chopped
• 1 (28 oz.) can tomatoes
• 1 (10 1/2 oz.) can tomato puree
• 1 tsp. sugar
• 2 tsp. Worcestershire sauce
• salt and pepper to taste
• 1/2 tsp. chili powder
• pinch of oregano (optional)
• 1/2 lb. grated cheese
• 1 small can mushrooms
• 1/2 lb. spaghetti