Preheat oven to 400 degrees.

Layer corned beef in the bottom of a lightly greased 9×9 baking dish.

Thoroughly drain sauerkraut and pat dry with paper towel. Sprinkle over the beef.

Spread salad dressing evenly over the sauerkraut.

Sprinkle Swiss cheese over salad dressing.

Place bread on top; spray lightly with cooking spray.

Bake covered for 20-25 minutes. Remove cover for the last 10 minutes to toast the bread.