Instructions:

Preheat Oven: Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish or a similar-sized oven-safe dish.
Prepare Bread: Lightly toast the rye bread slices. This will help the bread hold up better during baking. Cut the toasted bread into small squares or tear it into bite-sized pieces.
Assemble the Bake:
In a large mixing bowl, combine the corned beef, sauerkraut, and half of the shredded Swiss cheese.
Spread a layer of thousand island dressing on the bottom of the prepared baking dish.
Arrange half of the bread pieces in a single layer in the dish.
Spread half of the corned beef mixture over the bread.
Add another layer of bread pieces, then spread the remaining corned beef mixture on top.
Finish with the remaining bread pieces and sprinkle with the remaining Swiss cheese.
Add Butter and Seeds:
Brush the top layer of bread with melted butter.
Sprinkle caraway seeds over the top if using.
Bake: Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly and the top is golden brown.
Cool and Garnish: Allow the Baked Reuben to cool for about 5-10 minutes before serving. Garnish with chopped fresh parsley for added color and freshness.