Preheat the oven to 350 F. Cook the pasta according to package directions. Drain and place into a large bowl. Melt the butter into a large saucepan over medium heat. Cook the flour, and mix until lightly browned.
Pour in the milk, 2 cups shredded cheddar cheese, salt, and pepper. Mix until the cheese has fully melted and the sauce has thickened.
Mix the sauce with the pasta. Spread the mac and cheese into a greased baking dish. Top with the remaining cheddar cheese and crushed cheetos. Bake for 20-25 minutes.