01 - Boil spaghetti in a large pot of salted water until al dente. Reserve 1 cup of pasta cooking water, then drain the pasta.
02 - While spaghetti cooks, heat olive oil in a large skillet over medium heat. Sauté sliced garlic and red pepper flakes until the garlic turns golden and aromatic, about 2 to 3 minutes. Do not let the garlic burn.
03 - Add the sliced green olives to the skillet and cook for 1 to 2 minutes, stirring to integrate flavors.
04 - Add drained spaghetti to the skillet with a splash of reserved pasta water. Toss gently over low heat until the noodles are evenly coated and the sauce slightly emulsifies.
05 - Season with salt and freshly ground black pepper according to preference.
06 - Remove the skillet from heat. Sprinkle with chopped parsley and lemon zest if desired, and toss to distribute.
07 - Transfer to plates and serve immediately.