Start by boiling a large pot of salted water. Add your rigatoni and cook it until it’s just al dente—you want it firm to the bite since it’ll finish in the sauce. Don’t forget to reserve a cup of that pasta water before draining; it helps make the sauce silky later.
While the pasta cooks, heat a splash of olive oil in your skillet over medium heat. Remove the sausage from its casing if needed and add it to the pan. Break it up with a spoon and cook until it’s deeply browned and no longer pink. Once done, remove it and set aside.
In the same skillet, toss in your diced peppers and onion with a pinch of salt. Sauté until soft and slightly caramelized. Add in the garlic and red pepper flakes and stir until fragrant—about 30 seconds. Your kitchen will smell amazing by now.
Stir in the tomato paste and let it cook for a minute to deepen the flavor. Pour in the white wine to deglaze, scraping up any browned bits from the pan. Then add the crushed tomatoes and stir to combine. Let this simmer gently for a few minutes.
Return the browned sausage to the skillet and mix it into the sauce. Add your drained pasta and a splash of reserved pasta water. Stir everything well and let it cook together for 1–2 minutes so the sauce can cling to the pasta. Finish with freshly grated Parmesan.