Bring a large pot of salted water to a boil, then add the penne and cook until al dente, about 10 minutes. Drain and set aside.
Heat the olive oil in a skillet over medium heat until shimmering and fragrant.
Add the sliced garlic to the oil and cook, stirring constantly, until golden and aromatic—about 1-2 minutes. Be careful not to burn the garlic.
Pour in the crushed tomatoes and stir to combine with the garlic and oil. Bring the mixture to a gentle simmer—let it cook, stirring occasionally, until slightly thickened, about 8 minutes.
Add the red chili flakes and a pinch of salt to the sauce, stirring well. Taste and adjust seasoning if needed.
Transfer the cooked penne directly into the skillet with the spicy tomato sauce, tossing to coat each piece thoroughly and allowing the pasta to absorb the flavors for about 1-2 minutes.
Remove from heat and sprinkle with freshly chopped parsley for a burst of color and freshness.
Serve immediately on warm plates, enjoying the crisp, spicy aroma and glossy, vibrant sauce coating each piece of pasta.