Melt the butter in a large saucepan over medium heat. Add the flour and stir until combined. Slowly add the milk, whisking continuously until the mixture is thick and creamy.
Stir in the cheddar cheese, garlic powder, onion powder, paprika, Worcestershire sauce, mustard powder, black pepper, and salt until the cheese is melted and the sauce is smooth.
Add the cooked macaroni, sauerkraut, and corned beef to the sauce and stir to combine. Pour the mixture into a 9x13-inch baking dish.
Sprinkle the breadcrumbs on top of the mac and cheese and bake for 20 minutes, or until the top is golden brown and the cheese is bubbly.
Let cool for 5 minutes before serving.
Interesting Facts
The Reuben sandwich was created at the famous Reuben's Delicatessen in New York City in the early 1900s.
Corned beef is a type of beef that has been cured in a brine solution.