Cook the pasta in a large pot of boiling salted water until al dente according to the package instructions. Reserve about 1 cup of pasta water, then drain the pasta and set aside.
While the pasta is cooking, heat the olive oil in a large skillet over medium heat. Add the sliced garlic and red pepper flakes, and cook until the garlic is lightly golden and fragrant, about 1-2 minutes. Be careful not to let the garlic burn.
Add the cooked pasta to the skillet with the garlic and oil. Toss well to coat the pasta evenly with the oil and garlic mixture. If the pasta seems dry, add a splash of the reserved pasta water to moisten it.
Stir in the chopped parsley and season the pasta with salt to taste. Continue to cook for another minute or so, until everything is heated through and well combined.
Serve the Pasta Aglio e Olio hot, garnished with grated Parmesan cheese if desired. Enjoy!