Oh, so good!
Shape ground beef into 8 thin patties. Top each of 4 patties with either 1 tablespoon cheese or 1 tablespoon relish. Place remaining patties on top; seal edges well. Brown in skillet; spoon off fat.
Stir in soup and horseradish. Cover; cook over low heat for 20 minutes. Stir now and then. 4 servings.