Bring a large pot of lightly salted water to a boil. Cook pasta for 8 to 10 minutes, or until al dente; drain.
Heat a skillet over medium-low heat. Melt butter with garlic very slowly to avoid burning the garlic. Season with salt, freshly ground black pepper, and parsley. Sprinkle with cayenne pepper to taste, if desired.
Toss pasta into the skillet until well-coated with butter. Increase heat to medium, and cook until pasta is heated through and has absorbed some of the butter. Adjust seasoning with salt and pepper, if necessary. Serve with grated Parmesan cheese.
