Cook Spaghetti: Cook the spaghetti according to package instructions and drain, reserving ½ cup of the pasta water.

Sauté Garlic and Red Pepper Flakes: In a large pan, heat the olive oil over medium heat. Add the thinly sliced garlic and red pepper flakes, and sauté until the garlic is golden brown but not burnt, about 2-3 minutes. This step is crucial for infusing the olive oil with flavor.

Toss with Spaghetti: Add the cooked and drained spaghetti to the pan and toss to coat it thoroughly in the garlic-infused oil. Add the reserved pasta water as needed to create a light sauce that coats the pasta.

Season: Season with salt and pepper to taste.

Garnish and Serve: Garnish with chopped fresh parsley and lemon zest, if desired. Serve immediately.