Let's Cook

1. Step 1.

   In a medium bowl, stir together mayonnaise, sour cream, ketchup, relish, lemon juice, and horseradish. Season dressing with salt and pepper and set aside.

2. Step 2.

   Preheat oven to 350°F (180°C). Lay a sheet of aluminum foil on a rimmed baking sheet and place corned beef in the center. Bring foil edges up to form walls, then add 2 tablespoons (30ml) water to corned beef. Seal package well and transfer to oven until corned beef is heated through, about 10 minutes.

3. Step 3.

   Meanwhile, in a small saucepan or skillet, melt 1 tablespoon (15g) butter over medium heat until foaming. Add sauerkraut and cook, stirring occasionally, until any excess liquid has cooked off and sauerkraut is heated through and glossy, about 5 minutes. Keep warm.

4. Step 4.

   In a 12-inch stainless-steel or cast iron skillet, melt 2 tablespoons (30g) butter over medium-low heat. Add 4 bread slices and cook, rotating and moving slices around pan for even browning, until golden brown on bottom side, about 4 minutes. Transfer toasted bread slices to a work surface, toasted side down. Arrange remaining 4 untoasted bread slices in a row above them.

5. Step 5.

   Spread Russian dressing generously all over every bread slice. Mound corned beef, making sure to let any excess moisture drip off first, on the toasted bread slices. Mound sauerkraut on top of corned beef. Lay cheese slices over sauerkraut.

6. Step 6.

   Close sandwiches. Melt remaining 2 tablespoons (30g) butter in skillet over medium-low heat and add sandwiches, untoasted (top) side down. Cover with a lid that's slightly smaller than the skillet and cook, pressing down on the sandwiches with the lid, until cheese is melted, about 2 minutes. Uncover skillet and continue cooking, rotating and moving sandwiches around skillet and pressing down on sandwiches for even browning, until golden brown and crisp on second side, about 3 minutes longer.

7. Step 7.

   Transfer Reubens to a work surface, cut in half on the diagonal, and serve hot.