Fill a large pot with water, add salt, and bring to a boil. Add spaghetti or linguine, cooking for 8-10 minutes until al dente.

Before draining, reserve 1 cup of pasta water. Drain the pasta.

In a large skillet, heat olive oil and butter. Add minced garlic and crushed red pepper flakes, sauté for 1-2 minutes.

Pour reserved pasta water into the skillet. Simmer for 2 minutes.

Add drained pasta to the skillet, tossing to coat with the sauce.

Remove from heat, stir in Parmesan cheese, lemon juice, and zest.

Toss in parsley and black pepper before serving.