Cook pasta according to package directions, but until al dente (soft, but not fully cooked). Drain and set aside.
Heat milk in microwave for 6-8 minutes. In the meantime, melt butter in a large saucepan on medium heat. Whisk in flour and cook for 2 minutes, stirring constantly. (Should get bubbly.) Very Slowly, whisk the milk into the butter. Add the garlic and pepper. Add the cheese and stir until melted. Add the cooked pasta and stir gently until fully coated. Sprinkle top with parsley.