Step 1: In a large pot or Dutch oven, brown the Italian sausage over medium-high heat, breaking it into small crumbles. Drain excess fat if necessary, but leave about a tablespoon for flavor.
Step 2: Add the diced onion and bell pepper to the pot. Sauté for 5-7 minutes until the vegetables are softened and translucent.
Step 3: Stir in the minced garlic, tomato paste, dried oregano, and red pepper flakes. Cook for 1-2 minutes until fragrant.
Step 4: Pour in the marinara sauce and broth. Bring the mixture to a rolling boil over high heat.
Step 5: Add the noodles to the boiling soup. Reduce heat to medium and simmer for 10-12 minutes, or until the pasta is al dente.
Step 6: While the soup simmers, whisk together the ricotta, parmesan, and half of the fresh basil in a small bowl.
Step 7: Once the pasta is cooked, season the soup with salt and pepper. Ladle into bowls and top with a large spoonful of the ricotta mixture, a sprinkle of mozzarella, and remaining basil.