1. Preheat oven to 375°F (190°C) and lightly grease a 9×13-inch baking dish or line it with parchment paper.

2. Place sauerkraut in a fine-mesh strainer and press firmly to remove as much liquid as possible, then pat dry with paper towels.

3. Unroll crescent dough onto a lightly floured sheet of parchment paper; pinch seams together to form one solid rectangle and gently roll to roughly 12×15 inches.

4. Spread Thousand Island or Russian dressing (stirred together with Dijon mustard if using) down the center third of the dough, leaving the outer thirds and edges clear.

5. Sprinkle half of the shredded Swiss cheese over the dressing, then layer the sliced corned beef evenly over the cheese.

6. Distribute the well-drained sauerkraut over the corned beef and top with the remaining Swiss cheese.

7. Use a sharp knife to cut diagonal strips in the exposed dough along both sides of the filling, about 1 inch wide, then fold the top and bottom edges over the filling.

8. Fold the side strips over the center, alternating sides to create a braided look, and pinch any open seams to seal; carefully transfer the parchment and loaf into the prepared baking dish if needed.

9. Whisk the egg with 1 tablespoon water and brush the egg wash over the top and sides of the dough, then brush with melted butter and sprinkle with caraway seeds if using.

10. Bake for 25–30 minutes, or until the crust is deep golden brown and the filling is hot and bubbly at the seams.

11. Let the Reuben Crescent Bake rest for 10 minutes, then slice with a sharp serrated knife and serve warm with extra dressing on the side for dipping.