1Heat oven to 375°F.
2Melt 2 teaspoons butter in large nonstick skillet over medium heat. Add onion and thyme, cook and stir 3 to 4 minutes or until onion is tender.
3Remove from heat, stir in corned beef and horseradish-butter mixture.
4Meanwhile coat bottom and sides of 9-inch glass pie plate with remaining 1 teaspoon butter,set aside.
5Cut each potato half into 4 wedges. Arrange potato wedges in single layer over bottom and up sides of pie plate.
6Combine cheeses in small bowl. Sprinkle 1/2 of cheese mixture over potatoes on bottom of pie plate.
7Top with corned beef mixture and remaining cheese mixture. Press firmly with spatula to compact layers, cover with aluminum foil.
8Bake in 375°F oven 25 to 30 minutes or until heated through. Uncover, continue baking 3 to 5 minutes
9or until cheese is melted and edges begin to brown.
10Let stand 5 minutes. Cut into wedges.
Source: Family Features