Beefy Noodles Casserole Recipe - Ground Beef, Tomatoes, and Macaroni

Ingredients

• 1/2 lb (227 g) of lean ground beef, crumbled
• 1 chopped onion
• 1 can (15 oz (425 g)) of chili without beans
• 1 can (10 oz (283 g)) of diced tomatoes and green chilies, drained
• 2 tsp of dry mustard
• 1 cup of cooked elbow macaroni
• 1 beaten egg
• 1 cup of low-sodium shredded mozzarella cheese, divided