Heat olive oil in a large pot over medium heat. Add sausage, breaking up into bite sized pieces, and brown for about 5 minutes. Add onions and cook until softened, about 6 minutes. Add garlic, oregano, and red pepper flakes. Cook for 1 minute. Add tomato paste and stir well to incorporate. Cook for 3 to 4 minutes, or until the tomato paste turns a rusty brown color.

Add diced tomatoes, bay leaves, and chicken stock. Stir to combine. Bring to a boil and then reduce heat and simmer for 30 minutes. Add uncooked pasta and cook until al dente. Do not over cook or let soup simmer for a long period of time at this point, as the pasta will get mushy. Stir in basil and season to taste with salt and freshly ground black pepper.

While the pasta is cooking, prepare the cheesy yum. In a small bowl, combine the ricotta, Parmesan, salt, and pepper.

To serve, place a dollop of the cheesy yum in each soup bowl, sprinkle some of the mozzarella on top and ladle the hot soup over the cheese.