Bring a large pot of salted water to a boil. Add spaghetti and cook according to package instructions until al dente.

Reserve 1 cup of pasta water, then drain the pasta in a colander.

In a skillet, heat olive oil over medium heat. Add sliced garlic and red pepper flakes, cooking until garlic is golden and fragrant, about 2-3 minutes.

Add the drained pasta to the skillet, tossing to coat in the garlic oil. If the pasta seems dry, add reserved pasta water a little at a time until desired consistency is reached.

Stir in chopped parsley, salt, and black pepper. Mix well.

Serve immediately, garnished with grated parmesan cheese.