Brown pork sausage till no longer pink, breaking apart while it cooks.
Add onions and garlic then cook until softened.
Add tomato paste, Italian herbs, and red pepper flakes. Cook for another minute or two, or until the tomato paste turns a rusty brown color.
Add diced tomatoes and chicken stock. Stir to combine. Bring to a boil and then reduce heat and simmer for 30 minutes, covered. Stir occasionally.
Season with salt and pepper. Add uncooked pasta and cook until al dente. Do not overcook or let the soup simmer for a long period of time at this point, as the pasta will get mushy and absorb all the soup broth.
Cheesy Soup Topping
In a small bowl, combine the ricotta, Parmesan, and pepper.
To serve, place a dollop of the cheesy yum in each soup bowl, ladle the hot soup over the cheese, and sprinkle some of the mozzarella on top.