Heat 4 tablespoons of olive oil over medium heat. Stir 3 minced garlic cloves for 10 seconds. Add 1 finely chopped red cayenne chili and ½ teaspoon of chili flakes; cook for 1 minute.
Add 800g of canned crushed tomatoes, 1¼ teaspoons of kosher salt, and ¼ teaspoon of black pepper. Rinse the cans with a splash of water and add it.
Simmer for 15 minutes, stirring occasionally. Add a little sugar if the tomatoes taste sour.
Meanwhile, cook 400g of penne in boiling salted water according to the package directions. Reserve some cooking water, then drain.
Toss the pasta with the sauce over low heat, adding enough reserved water to make it coat the pasta. Serve immediately.
