Brush steaks with melted butter. Snip fat to prevent curling, and grill for 7-8 minutes each side. - To make sauce, gently fry onions in remainder of butter until cooked. Remove from heat and stir in flour gradually. Add stock. Return to heat. Add sugar and bring to the boil. Simmer gently for about 2 minutes to cook flour. If sauce seems a little thick, add more water. Add whiskey and season to taste. Place gammon steaks on a warmed serving platter and pour on sauce. - Serve with peas and carrots, or sauteed potatoes.