Steps
1. Bring a pot of salted water to a boil and cook the spaghetti until al dente, about 8 minutes.
2. While the pasta cooks, heat olive oil in a pan over medium heat.
3. Add the sliced garlic and red chili flakes to the oil, sauté gently until garlic is golden but not burnt.
4. Drain the spaghetti, reserving a little pasta water.
5. Toss the spaghetti in the garlic chili oil, adding a splash of reserved pasta water to loosen the sauce.
6. Stir in chopped parsley and season with salt.
7. Serve hot, topped with grated Parmesan if desired.