Preheat oven to 375°F (190°C) and grease a 9×13-inch baking dish.
Unroll one can of crescent dough and press it into the bottom of the baking dish.
Layer half of the Swiss cheese on top of the dough.
Spread the corned beef evenly, then add the drained sauerkraut.
Drizzle the Thousand Island dressing over the sauerkraut.
Top with the remaining Swiss cheese slices.
Unroll the second can of crescent dough and place it on top, sealing the edges.
Brush the top with beaten egg and sprinkle with caraway seeds if using.
Bake for 25-30 minutes or until golden brown.
