Corned Beef and Potato Casserole

Preheat oven to 375 degrees. Butter a 9 inch glass pie dish. Melt 2 tsp. butter in a large skillet. Add onion and thyme. Cook, stirring frequently, 4 minutes. Remove skillet from heat and stir in brisket, 1 tbsp. butter and horseradish. Arrange potato wedges over bottom and up sides of prepared pie dish. Stir together Swiss and Parmesan cheeses in a small bowl. Sprinkle half of cheese mixture over potatoes. Spoon corned beef mixture over potatoes. Sprinkle remaining cheese over beef. Press down with a spatula. Cover casserole with foil. Bake casserole 25 to 30 minutes until heated through. Let stand 5 minutes before serving.