In a large pot or Dutch oven, brown the ground beef over medium heat. Once cooked, drain any excess fat.
Add the diced onion and garlic to the pot. Sauté until the onion is soft, about 3-4 minutes.
Stir in the crushed tomatoes, beef broth, dried basil, dried oregano, red pepper flakes (if using), and broken lasagna noodles. Bring to a simmer.
Cover the pot and let it simmer for about 20 minutes, stirring occasionally, until the noodles are cooked al dente.
While the soup is simmering, in a small bowl, combine the ricotta cheese with a pinch of salt and pepper.
Once the noodles are cooked, remove the pot from heat. Stir in the ricotta cheese mixture, mozzarella cheese, and Parmesan cheese until well combined.
Taste and adjust seasoning with salt and pepper if needed.
Serve hot, garnished with fresh basil if desired.