In a large soup pot or Dutch oven, cook and crumble the sausage and ground beef over medium-high heat. Add the onions and garlic and cook until softened. Stir in Italian seasoning and red pepper flakes.

Add tomato paste, diced tomatoes, chicken broth, salt, and pepper. Bring to a boil, then reduce heat and simmer. Add the pasta and cook until al dente, about 8-10 minutes.

While the pasta cooks, mix ricotta, Parmesan, and mozzarella in a small bowl.

Remove the soup from heat and serve in bowls topped with a generous amount of cheese mixture.