Bring a large pot of salted water to a boil. Add spaghetti and cook until al dente, about 8-10 minutes. Reserve 1/4 cup of pasta water before draining.

In a skillet, heat olive oil over medium-low heat. Add garlic and sauté for 1-2 minutes until golden and fragrant.

Stir in chili flakes, then add shrimp and cook for 3-4 minutes until they turn pink and opaque.

Pour reserved pasta water into skillet. Increase heat and simmer for 2 minutes to thicken.

Add drained spaghetti to skillet, tossing to combine with sauce. Stir in parsley and Parmesan, serve immediately.