To prepare steak, trim fat from steak. Place whiskey and soy sauce in a large zip-top plastic bag. Add steak; seal and marinate in refrigerator 24 hours, turning bag occasionally.
To prepare horseradish cream, combine yogurt, horseradish, mustard, and garlic in a small bowl. Cover and chill.
To prepare rub, combine sugar and next 5 ingredients (sugar through salt). Remove steak from bag; discard marinade. Rub sugar mixture over steak; chill 30 minutes.
Prepare grill or broiler.
Place steak on a grill rack or broiler pan coated with cooking spray, and cook 8 minutes on each side or until desired degree of doneness. Cut steak diagonally across grain into thin slices. Serve with the horseradish cream.