Reuben Mac N Cheese

Name: Reuben Mac N Cheese
Ingredients: salt; 1 lb cavatappi pasta, hallow corkscrew shaped pasta or, other short cut; 2 slices rye bread; 3 tablespoons butter, plus; some butter, for buttering toast; fresh parsley leaves; 1 teaspoon paprika; 3 tablespoons all-purpose flour; 2 cups milk; 1⁄4 cup spicy brown mustard (recommended ( Gulden's); 1 cup shredded swiss cheese; 1 cup shredded gruyere; 1 cup shredded yellow cheddar cheese; 3⁄4 lb good quality deli corned beef, sliced as thick as bacon, chopped; 1 lb sauerkraut, rinsed and well drained