Brown the beef and sausage: Heat a large pot over medium-high heat and add the ground beef and beef sausage. Cook, breaking it up with a spoon, until no pink remains, about 7 minutes, then drain excess fat.

Cook the onion: Add the diced onion to the pot and cook until translucent and softened, about 4 minutes. Stir occasionally so it doesn't catch on the bottom.

Add the garlic: Stir in the minced garlic and cook for 30 seconds until fragrant. Keep stirring so it doesn't burn.

Pour in tomatoes and broth: Add the crushed tomatoes and chicken broth, scraping up any browned bits stuck to the bottom of the pot. Stir in the Italian seasoning and red pepper flakes if using.

Simmer the base: Bring the soup to a gentle boil, then reduce the heat and simmer uncovered for 15 minutes to concentrate the flavors and thicken the broth slightly.

Cook the pasta: Stir the small pasta into the simmering soup and cook until just tender, about 9 minutes. Stir occasionally so it doesn't stick to the pot.

Remove from heat: Turn off the heat and let the soup sit for 1 minute before adding cheese, so it isn't at a hard boil.

Stir in ricotta: Add the ricotta cheese in spoonfuls, stirring gently until it melts into the broth and turns it creamy, without clumping.

Add mozzarella and parmesan: Stir in the shredded mozzarella and grated parmesan until fully melted and the broth looks smooth and glossy.

Season and taste: Taste the soup and add salt and black pepper as needed. Adjust the red pepper flakes if you want more heat.

Serve warm: Ladle the soup into bowls and top with chopped fresh basil before setting the bowls on the table.