Combine onion, half the cream cheese, liverwurst, mustard and Worcestershire sauce. Blend well. Place in a plastic lined bowl and chill until firm. To serve, unmold on a serving plate. Combine remaining cream cheese with milk. Spread over pate. Sprinkle with chopped parsley. Garnish with onion rings, dipped in paprika. Serve with a choice of crackers or melba toast.