Bring a large pot of salted water to a boil. Add rigatoni and cook until al dente, about 8-10 minutes. Reserve 1 cup of pasta water before draining.

In a skillet, heat olive oil over medium heat. Add garlic and tomato paste. Sauté for 4-5 minutes until caramelized.

Remove from heat and whisk in heavy cream gradually. Return to low heat and simmer for 3-5 minutes.

Stir in crushed red pepper flakes and dried basil. Season with salt and black pepper to taste.

Incorporate Parmesan cheese and butter, stirring until melted. Add reserved pasta water until desired consistency is reached.

Toss the drained rigatoni into the sauce, mix gently, then serve hot garnished with extra Parmesan and parsley if desired.