Place 2 cups whole milk, 1 3/4 cups water, and 1 teaspoon kosher salt in a large saucepan and bring to a boil over medium-high heat. Reduce the heat to medium, then add 1 pound macaroni.

Simmer, stirring frequently, until the pasta is tender, about 10 minutes. Meanwhile, shred 8 ounces sharp cheddar cheese (about 2 cups).

Remove the saucepan from the heat. Add the cheese and 2 tablespoons unsalted butter, and stir until melted and combined. Top with ground black pepper if desired. Serve immediately.