Trim fat from veal chops. Place 2 tablespoons margarine in a large nonstick skillet. Place over medium-high heat until margarine melts. Add chops, and cook 3 to 4 minutes on each side or until browned. Transfer veal to a serving platter, and keep warm. Reserve drippings in skillet.
Saute leeks and mushrooms in 1 tablespoon margarine in skillet over medium-high heat until tender. Stir in wine, whipping cream, horseradish, and crushed peppercorns. Cook, uncovered, over medium-low heat, stirring frequently, 8 to 10 minutes or until slightly thickened. Spoon sauce evenly over veal, and sprinkle with parsley.