Ingredients

Instructions

  1. Heat extra-virgin olive oil in a 12" skillet over medium-low heat.
  2. Add minced onion and cook, stirring, until soft, about 12 minutes.
  3. Add garlic and cook, stirring, for 2-4 minutes.
  4. Add crushed red pepper flakes; cook for 1 minute more.
  5. Increase heat to medium, add puréed tomatoes and season lightly with kosher salt; cook, stirring occasionally, until sauce thickens slightly and the flavors meld, about 20 minutes.
  6. Remove pan from heat, stir in basil sprigs, and set aside.
  7. Meanwhile, bring water to a boil in a 5-qt. pot. Season with salt; add spaghetti and cook, stirring occasionally, until about 2 minutes before tender.
  8. Drain pasta, reserving 1/2 cup pasta cooking water.
  9. Discard basil and heat skillet over high heat. Stir in reserved pasta water to loosen sauce; bring to a boil.
  10. Add pasta and cook, stirring, until sauce coats pasta and pasta is al dente, about 2 minutes.
  11. Remove pan from heat; add butter and cheese; toss until cheese melts.
  12. Transfer to warm bowls; serve with more cheese, if desired.