Start by bringing a large pot of salted water to a rolling boil. Add the spaghetti and cook until al dente, about 8-10 minutes.

Meanwhile, heat 1/3 cup of olive oil in a skillet over medium heat. Add the sliced garlic and sauté for about 2-3 minutes until golden and fragrant.

In the last minute of cooking the garlic, add 1/2 teaspoon of red pepper flakes. Stir well and combine for another minute before removing from heat.

Reserve 1/2 cup pasta water, then drain the spaghetti. Add it to the skillet with the garlic oil and toss gently.

Slowly add reserved pasta water as needed to reach desired sauce consistency, mixing thoroughly for 1-2 minutes.

Season with salt and pepper to taste, and stir in the chopped parsley. Serve immediately, optionally topping with grated Parmesan cheese.