1. In a small bowl, mix together mayo, ketchup, onion, hot sauce, and paprika and set aside. 2. Butter a pan. Layer the ingredients for the Reuben: start with three fourths of the corned beef, top with the sauerkraut. Sprinkle the caraway seeds. Drizzle the dressing. Top with the remaining meat, and then top with Swiss Cheese. 3. Bake at 400F for 15 minutes until the cheese has melted and is bubbling.