Brown the Italian sausage in a skillet, breaking it up as it cooks, until no longer pink; drain excess fat. Add the browned sausage to the Crockpot and spread it out for even heating.

Add the diced onion and minced garlic to the Crockpot, then pour in the crushed tomatoes, diced tomatoes, and broth. Stir in the tomato paste, Italian seasoning, dried basil, red pepper flakes, and oregano until the mixture looks evenly combined.

Cook on Low for 5-7 hours until the flavors deepen and the broth looks thickened around the edges. If using High, cook for 3-4 hours until everything is hot and well simmered.

In the last 30 minutes, add the broken lasagna noodles and increase to High if you cooked on Low. Cook until the noodles are tender and the soup thickens slightly, with noodles visibly softened.

Season with salt and pepper to taste, then stir and taste again for balance. Serve hot, with a thick, creamy cheese dollop in each bowl.

Mix the ricotta, shredded mozzarella, and parmesan together, then fold in fresh basil. Spoon a generous dollop into each bowl so it starts melting into the hot tomato broth.