Boil salted water in a 3-quart pot. Add spaghetti and cook for about 7-8 minutes, until al dente. Drain, reserving 1 cup of pasta water.
In a 10-12 inch saute pan, melt butter and olive oil over medium heat. Add garlic and stir, cooking for about a minute.
Add spaghetti, 1 cup of pasta water, cream cheese and heavy cream to the skillet. Bring to a boil and add shredded cheeses. Stir constantly until cheeses are melted and pasta is completely coated; about a minute. Reduce heat and continue to cook and stir until sauce is thickened and reduced; about 1-2 minutes.
Remove from heat and stir in parsley. Taste and add salt and pepper as desired.
Serve hot, and garnish with more fresh parsley and some fresh grated Parmesan, if desired.
Notes
Easily double the recipe to serve as the main course, or make it as is to serve as a side dish.I always love the classic pairing of garlic bread and a green salad with any type of pasta.