Easy Creamy Tomato Rigatoni (Cozy 35-Minute Pasta)

Ingredients

• 1 lb (450 g) dried rigatoni
• Kosher salt, for the pasta water
• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• 1 small yellow onion, finely diced
• 4 cloves garlic, minced
• 1/4 teaspoon red pepper flakes, optional
• 2 tablespoons tomato paste
• 1 can (28 oz / 795 g) crushed tomatoes
• 1 teaspoon kosher salt, plus more to taste
• 1/2 teaspoon black pepper
• 1/2 cup (120 ml) heavy cream
• 3/4 cup (75 g) freshly grated parmesan cheese, plus more for serving
• 1/2-1 cup reserved pasta water
• 1/4 cup chopped fresh basil or parsley