Heat the olive oil and butter over medium-high heat. Add the ground beef and diced onion, breaking the meat into small pieces as it cooks. Stir occasionally for 6–8 minutes, until the beef is no longer pink and the onions are soft and lightly golden.

Add the minced garlic and tomato paste to the pot. Cook, stirring constantly, for 1–2 minutes. The tomato paste should darken in color and start to smell sweet and caramelized.

Pour in the crushed tomatoes and broth. Stir well, scraping the bottom of the pot to lift any browned bits. Add the Italian seasoning, dried basil, thyme or oregano, paprika, black pepper, and red pepper flakes if using. Bring the mixture to a steady simmer and taste for salt, adding a pinch if needed.

Break the lasagna noodles into bite-size pieces and stir them into the pot. Lower the heat to medium, and cook 10–12 minutes, stirring every few minutes to keep the noodles from sticking together or to the bottom. The soup will thicken slightly as the noodles release starch.

While the noodles simmer, stir together the ricotta and parmesan in a small bowl. Set aside near the stove so it’s ready when you serve.

When the noodles are al dente, reduce the heat to low and stir 1 cup of shredded mozzarella into the soup. Keep stirring until it melts into the broth and turns the soup glossy and slightly creamy. Taste again and adjust salt or pepper.

Ladle the lasagna soup into warm bowls. Top each with a generous spoonful of the ricotta–parmesan mixture, a sprinkle of the remaining mozzarella, and fresh basil or parsley. Let the cheese soften and melt slightly into the hot soup before serving.