In a large pot or deep skillet, combine the uncooked pasta, water, whole milk, minced garlic, salt, and black pepper.
Bring the mixture to a boil over medium-high heat, stirring occasionally to prevent the pasta from sticking.
Once boiling, reduce the heat to medium-low and simmer uncovered, stirring frequently, until the pasta is cooked al dente and most of the liquid is absorbed, about 12 to 15 minutes.
Remove the pot from heat and immediately stir in the unsalted butter until melted.
Add the shredded sharp cheddar cheese and grated Parmesan cheese to the pot, stirring until the cheeses are fully melted and the sauce is creamy.
Sprinkle the chopped fresh parsley over the pasta and stir to combine.
Serve the garlic cheese pasta hot.