Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish or line it with parchment paper for easy cleanup.
In a large mixing bowl, toss the cubed rye bread with melted butter and caraway seeds until evenly coated. Spread the bread cubes evenly across the bottom of the prepared baking dish to form the base layer.
Spread half of the shredded corned beef evenly over the bread layer. Top the corned beef with half of the sauerkraut, spreading it out in an even layer. Sprinkle 1 cup of shredded Swiss cheese over the sauerkraut. Repeat the layers: add the remaining corned beef, followed by the remaining sauerkraut, and another cup of Swiss cheese.
Drizzle the Thousand Island dressing evenly over the top layer of Swiss cheese.
Bake in the preheated oven for 25–30 minutes, or until the cheese is bubbly and golden brown, and the edges are crispy.
Remove the bake from the oven and let it cool for 5–10 minutes before slicing. Cut into squares and serve warm.
