Start by adding the sausage to a large pot over medium-high heat. Cook it for about 5 minutes, breaking it apart as it browns. Drain a little fat if needed, but leave some for flavor. Add the chopped onion and garlic, letting them soften and become fragrant for another 4–5 minutes.
Pour in the crushed tomatoes, beef broth, water, and Italian seasoning. Add the broken lasagna noodles. Turn up the heat until the pot begins to boil, then reduce to a gentle simmer and cook for about 15 minutes. Stir occasionally so the noodles don’t stick to the bottom.
When the noodles are tender, stir in the fresh basil. Adjust seasoning with salt and pepper. Serve the soup hot, topped with ricotta, mozzarella, and Parmesan for that true lasagna comfort.