Finely grate cheese into a bowl. Add butter and mix well.
Stir in port, green onions, caraway seeds, mustard and Worcestershire sauce. Mix thoroughly until well combined.
Spoon mixture into a serving dish. Cover with walnuts and press walnuts down lightly into mixture. Chill at least 2 hours. Serve with crisp crackers or Melba toast and garnish with parsley sprigs, if desired.
VARIATION: Add 1 teaspoon chopped fresh herbs and a few pinches cayenne pepper to taste.
NOTE: This spread will keep in a refrigerator for up to 5 days.