Preheat oven to 375 degrees F (190 degrees C). Lightly grease a 10 inch casserole dish.
Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
Melt butter in a small saucepan over medium heat. Stir in the flour and cook until a roux forms. Stir in the milk, salt and pepper; cook, stirring constantly, until sauce is smooth and thick and coats the back of a spoon. Remove from heat and stir in cheese.
Combine cooked pasta and cheese sauce; transfer to prepared dish.
Bake in preheated oven for 15 minutes, or until heated through.
