Step 1

Place the beef, salt, and pepper in a 6-quart or larger slow cooker. Use a wooden spoon to gently break up the meat. Add the broth, marinara sauce, onion, garlic, Italian seasoning, and Parmesan rind, if using. Stir well to combine.

Step 2

Cover and cook on the HIGH setting for 4 to 5 hours or on the LOW setting for 7 to 8 hours. Stir in the noodles. Cover, set to LOW, and cook until the noodles are tender, 25 to 35 minutes.

Step 3

Remove and discard the Parmesan rind. Ladle the soup into bowls and top with the mozzarella, ricotta, and basil. Serve immediately.