In a large pot, bring salted water to a boil and cook the rigatoni according to package instructions until al dente. Reserve a cup of pasta water and then drain the pasta.
In a large skillet, heat the olive oil over medium heat. Add the Italian sausage, breaking it apart with a wooden spoon, and cook until browned and cooked through, about 7-10 minutes.
Once the sausage is cooked, add the chopped onion and diced bell pepper to the skillet. Sauté for about 5 minutes, until the onion is translucent.
Stir in the minced garlic and cook for an additional minute until fragrant.
Pour in the crushed tomatoes and stir in the dried basil, dried oregano, salt, and pepper. Let the sauce simmer for about 10 minutes, allowing it to thicken slightly.
Add the cooked rigatoni and baby spinach to the skillet, tossing everything together. If the sauce is too thick, add some reserved pasta water to reach your desired consistency.
Remove the skillet from heat and stir in the ricotta cheese until well combined, creating a creamy texture throughout.
Serve the rigatoni in bowls, topped with grated Parmesan cheese and fresh basil leaves for garnish.
Notes
Add more vegetables or spices according to your taste.