Cook macaroni according to package directions. Drain. Melt butter in 3-quart saucepan until sizzling. Stir in flour, salt, and pepper. Add milk and cook over medium heat, stirring constantly, until mixture boils and thickens, or about 5 to 7 minutes.
Reduce heat to low. Stir in Cooper® cheese and continue to stir constantly until cheese is melted, or about 5 to 7 minutes.
Add cooked macaroni and stir well. Serve immediately.
Follow all steps above, then spoon mixture into a 3-quart casserole dish. Top with breadcrumbs and bake at 350°F for 25 to 30 minutes or until brown and bubbly.