2. Cook bacon until crisp, cool then crumble, reserve.
3. Melt butter in a medium saucepan over medium heat, add flour and cook 1 minute, stirring constantly. Stir in milk, salt and pepper; continuing to stir frequently until mixture boil and thickens.
4. Bring a pot of lightly salted water to a boil. Add the macaroni and cook for 8–10 minutes or until al dente; drain.
5. Add the sharp cheddar and American cheeses to the milk mixture; stir until cheese is melted. Combine the cheese sauce with the macaroni, frank slices and bacon crumbles. Transfer into a 2-quart lightly sprayed baking dish. Top with panko breadcrumbs.
6. Bake in preheated oven for 30 minutes, or until hot and bubbly.