Mix milk, sugar, butter and salt in a pot. Bring to a full boil, then boil for 5 minutes stirring constantly. Remove from heat. Add marshmallows, chocolate chips, flavoring and walnuts. Stir vigorously until marshmallows are melted and thoroughly blended. Pour into 20 cm square pan. Chill. Makes about 2 pounds. Origin: My Mom, Shirley Whittaker, Richmond B.C. Canada. Shared by: Sharon Stevens Oct/91