Step 1

In a medium saucepan of boiling salted water, cook penne until just short of al dente, about 1 minute less than the package recommends.

Step 2

Meanwhile, in a large skillet, combine oil, garlic, and pepper flakes. Cook over medium heat until garlic is very lightly golden, about 5 minutes. (Adjust heat as necessary to keep it gently sizzling.)

Step 3

Add tomatoes, stir to combine, and bring to a bare simmer. When pasta is ready, transfer it to sauce using a strainer or slotted spoon. (Alternatively, drain pasta through a colander, reserving 1 cup of cooking water. Add drained pasta to sauce.)

Step 4

Add about 1/4 cup pasta water to sauce and increase heat to bring pasta and sauce to a vigorous simmer. Cook, stirring and shaking the pan and adding more pasta water as necessary to keep sauce loose, until pasta is perfectly al dente, 1 to 2 minutes longer. (The pasta will cook more slowly in the sauce than it did in the water.)

Step 5

Continue cooking pasta until sauce thickens and begins to coat noodles, then remove from heat and toss in cheese and parsley, stirring vigorously to incorporate. Stir in a drizzle of fresh olive oil, if desired. Season with salt and serve right away, passing more cheese at the table.