Cook the macaroni according to package directions; drain and set aside.
In a saucepan, melt the butter over medium heat. Stir in the flour and cook for a few minutes. Remove from heat and whisk in the milk, dry mustard and paprika, adding the milk a little at a time.
Return to heat and stir until the sauce begins to thicken. Add about three quarters of the cheese and cook until the sauce is thick and cheese is melted.
Stir in the macaroni and transfer to an ovenproof dish. Top with remaining cheese, breadcrumbs and a sprinkle of paprika.
Bake for 30 minutes or until browned.