Who serves the best Reuben sandwich in town? Surprise, surprise -- it's the humble kitchens at the various franchised Penn Station East Coast Subs grinder joints. They use the same corned beef, sauerkraut, Swiss cheese and Thousand Island dressing as most folks, but their secret is serving it very hot on open-faced, buttered French bread. They bring it to your table, and when you fold over the bread into a sandwich proper, a lot of heat gets trapped in there with the ingredients. The French bread acts as an insulating pocket, and the meat, cheese, kraut and sauce melt together into the Reuben of fantasy. Try it and see.