Preheat oven to 400 degrees F. Cook macaroni in large saucepan as directed on package. Once finished, rinse macaroni under cold water and drain well. Set aside. Melt butter in same saucepan on medium heat. Sprinkle in flour, mustard, pepper and garlic powder. Cook and stir for 2 minutes or until well blended. Gradually stir in milk until smooth and continue stirring constantly, cooking sauce for 3 minutes until thick. Add cheese and stir until melted and smooth. Remove pan from heat and add macaroni, tossing gently to coat. Pour into greased 13x9 inch baking dish. In a small dish, mix panko and paprika then sprinkle evenly over top of macaroni. Bake 25-30 minutes or until bubbly and golden brown on top. Let stand 5 minutes before serving.