Preheat the oven to 350°F. Cook the pasta in salted boiling water until al dente. Drain and set aside.

Heat the oil in a large cast iron skillet over medium-high heat. Brown the turkey sausage, breaking it apart as it cooks. Drain excess grease if needed. Add onion and bell pepper; sauté 5-7 minutes until softened. Stir in garlic and cook for 1 minute. Stir in tomato paste, basil, oregano, red pepper flakes, salt, and pepper. Cook for another minute. Deglaze the skillet with the broth, scraping up browned bits; cook until mostly evaporated. Add crushed tomatoes and tomato sauce and bring to a simmer. Reduce heat to low, cover, and simmer for 20-25 minutes. Stir in heavy cream, ricotta and spinach until spinach wilts. Mix in cooked pasta and 1 cup mozzarella until evenly coated. Then top with remaining mozzarella and Parmesan. Bake the skillet in the oven for 25-30 minutes, until the cheese is bubbly and lightly browned. 

Let cool slightly, garnish with fresh herbs, and serve straight from the cast iron skillet. Enjoy!