Prepare macaroni according to package directions.
Melt 1/4 cup butter over low heat. Add flour; cook 1 minute, stirring constantly until smooth. Gradually add milk; cook over medium heat, stirring constantly, until thickened and bubbly. Stir in salt and pepper.
Place half of macaroni in a lightly greased 3-quart casserole; top with 1 cup cheese. Repeat layers. Pour white sauce over top, and sprinkle with remaining 1 cup cheese. Dot with 2 tablespoons butter. Bake, uncovered, at 400° for 35 to 40 minutes or until lightly browned.