Bring the sauce to a simmer and cook for 20 minutes or until the desired consistency is reached.
Stir in the Parmesan until it is fully melted then add the spaghetti and toss until all of the pasta is fully coated.
Serve with freshly grated Parmesan cheese, if desired.
Notes
Storage: Store leftover spaghetti with arrabbiata sauce in an airtight container in the refrigerator for up to 4 days. Or store leftovers in a freezer safe container in the freezer for up to 3 months.