1. Melt butter in a large saucepan over medium heat; whisk in flour until fully incorporated, about 3 minutes. Slowly whisk in milk; bring to a simmer and continue whisking until sauce has thickened, about 10 minutes.

2. In a medium bowl, combine Monterey Jack, Gruyere, Comte, and cheddar cheeses. Whisk cheeses into simmering milk mixture, about 1/2 cup at a time, letting each addition melt before adding the next. Add 2 teaspoons salt, and pepper; stir to combine.

3. Meanwhile, bring a large pot of water to a boil over high heat; generously season with salt and return to a boil. Add pasta and cook according to package directions. Drain and transfer saucepan with cheese sauce, and fold to combine; serve immediately.