Preheat the oven to 400 degrees. Heat a large, wide oven-safe pot skillet, add the pork sausage and crumble with a wooden spoon. Cook until pork is cooked through, about 10 minutes. Add garlic and stir for 1 minute. Add the tomato paste and stir well to coat the meat in the tomato paste. Add the pumpkin and stir to combine. Then, add the broth, season with salt and pepper, and stir well to combine. Add the ziti and stir to combine. Add dollops of the ricotta throughout the pasta, by the tablespoon. Sprinkle over the top with the mozzarella cheese. Cover and cook for 40 minutes or until ziti is cooked through and al dente. If you don’t like crispy pasta edges, make sure all the noodles are mostly submerged in the liquid (although, the crispy parts are the best!)

Uncover and sprinkle with red pepper flakes, if using. Serve.