Bring a large pot of salted water to a boil, then add the penne and cook until just al dente. Drain and set aside.
Heat olive oil in a large skillet over medium heat, and once shimmering, add the chopped garlic. Sauté until fragrant and just beginning to turn golden, about 30 seconds to 1 minute.
Stir in the red chili flakes and cook for another 15 seconds, releasing their heat and aroma into the oil.
Add the crushed tomatoes to the skillet, stirring to combine with the garlic and chili flakes. Bring the sauce to a gentle simmer, and season with salt to taste.
Let the sauce simmer for about 8–10 minutes, stirring occasionally, until it thickens slightly and the flavors meld together.
Add the cooked pasta directly to the skillet, tossing to coat each piece evenly with the fiery sauce. Allow it to cook together for 1–2 minutes so the pasta absorbs some of the sauce’s heat and flavor.
Once coated and heated through, transfer the arrabbiata pasta to serving bowls, and enjoy immediately while bubbling hot and full of bold flavor.