Cook the macaroni according to the package directions. Drain and reserve.
Reserve 2 tablespoons each of the smoked Cheddar, sharp Cheddar and mild cheese to sprinkle over the macaroni and cheese at the end.
Combine the half-and-half, milk, 1/2 teaspoon kosher salt, garlic salt and pepper in a large pot and place it over medium-high heat. Bring to a low boil and gradually whisk in the remaining smoked Cheddar, sharp Cheddar and mild cheese, stirring to make a creamy sauce. Mix in the macaroni and season with kosher salt to taste. Pour into a baking dish and top with the reserved smoked Cheddar, sharp Cheddar and mild cheese.
Recipe courtesy of G. Garvin