Brown the ground beef in a skillet over medium heat. Add the onion and cook until softened, then stir in the garlic for 30 seconds. Drain any excess grease.
Transfer the beef mixture to the crockpot.
Add the marinara sauce, diced tomatoes, tomato sauce, beef broth, tomato paste, Italian seasoning, basil, oregano, salt, and black pepper. Stir well.
Cover and cook on Low for 6 to 7 hours or High for 3 to 4 hours.
About 30 minutes before serving, stir in the broken lasagna noodles.
Cover and continue cooking until the noodles are tender.
Ladle the soup into bowls and top each serving with mozzarella, a spoonful of ricotta, Parmesan cheese, and chopped parsley.
Serve immediately.