Step 1

Bring a large pot of salted water to a boil. Add the pasta and cook according to the package instructions until al dente.

Step 2

About 5 minutes before the pasta is done, in a medium (10-inch) cold skillet combine the oil, garlic and crushed red pepper flakes. Set over medium heat and cook, swirling the pan occasionally, until the garlic turns pale golden, about 5 minutes. (Don’t let the garlic get too brown.) Add half the parsley and cook, stirring constantly, until aromatic, about 30 seconds.

Step 3

When the pasta is cooked, reserve 1 cup of the pasta cooking water and use tongs to transfer the pasta to the skillet and toss until combined with the sauce, adding a splash of the reserved pasta water if it looks dry. (Alternatively, reserve 1 cup of the pasta cooking water and drain the pasta in a strainer, transfer the pasta to the skillet, add 2 to 4 tablespoons of the reserved pasta water and toss until combined.) Remove from the heat. Taste, and season with salt, if needed. Toss with the remaining parsley, divide among bowls, sprinkle with cheese if using, and serve hot.