Cook the rigatoni according to the package instructions until al dente. Save one cup of pasta water, drain and set aside.
In a large saucepan, heat the olive oil over medium heat. Add the red pepper flakes, chopped onion and minced garlic and cook until softened, about 5 minutes.
Add the tomato paste, stir to combine and cook for 1 minute
Pour in the chicken broth and heavy cream. Season with salt and pepper, to taste stir for 1 minute.
Add half of the parmesan and 2 to 3 tablespoons of pasta water. Use more if you want a thinner sauce, less if you want thicker
Let the sauce simmer for 10-15 minutes, or until the sauce has thickened.
In a large serving bowl, mix the cooked rigatoni with the spicy sauce. Toss well to ensure the pasta is coated evenly.
Sprinkle the grated Parmesan cheese over the top and garnish with fresh basil leaves.
Serve the spicy rigatoni hot and enjoy!
