Preheat the Oven: Start by preheating your oven to 375°F (190°C). This will ensure that your casserole bakes evenly and gets that lovely golden crust.
Prepare the Baking Dish: Lightly grease a 9x9-inch baking dish with cooking spray or butter to prevent sticking.
Make the Crust: Unroll the crescent roll dough and press it into the bottom of the baking dish, sealing the seams to form a solid crust.
Bake the Crust: Place the crust in the oven and bake for 7–8 minutes or until it’s just lightly golden.
Layer the Ingredients: Once the crust is partially baked, spread the Thousand Island dressing over it evenly. Follow by layering the chopped corned beef and drained sauerkraut on top.
Top with Cheese: Sprinkle the shredded Swiss cheese over the entire dish. If you’re using caraway seeds for that classic rye flavor, sprinkle them on now.
Brush with Butter: For a beautiful finish and added flavor, lightly brush melted butter over the top of the cheese layer.
Final Bake: Return the casserole to the oven and bake for an additional 15–20 minutes, or until the cheese is melted and bubbly.
Cool and Serve: Let the casserole cool slightly before slicing it. Serve warm with extra Thousand Island dressing or pickles on the side for a delightful touch.