Prepare your ingredients by gathering all ingredients, dicing the corned beef, rinsing and draining the sauerkraut, and mixing the dressing ingredients.

Combine the diced corned beef, drained sauerkraut, and shredded Swiss cheese, pouring the dressing mixture over the top and folding until well combined.

Preheat the oven to 375°F (190°C) and grease a 9x13-inch baking dish. Spread the beef mixture evenly in the dish, sprinkle with Swiss cheese and rye breadcrumbs.

Bake in the preheated oven for 25-30 minutes until the cheese is bubbling and golden brown.

Allow the casserole to rest for 5-10 minutes before slicing and serving warm.