Prepare the sauce while the pasta water comes to a boil and the pasta cooks. In a skillet, heat 2–3 tablespoons of extra virgin olive oil with the crushed garlic clove and the chili pepper (seeded and finely chopped). Keep the heat moderate so the oil becomes infused with flavor without burning.
Cut the tomatoes in half, remove the seeds, and cut them into small cubes.
Remove the garlic clove from the pan and add the diced tomatoes. Cook for a few minutes until you obtain a light, brightly colored sauce. Once the penne is cooked al dente, drain and transfer directly into the sauce.
Toss well so the pasta is evenly coated, then finish with a drizzle of raw olive oil. Plate the pasta, garnish with a sprinkle of fresh parsley and grated Pecorino Romano to taste, and serve the penne all'arrabbiata immediately.