Up to 3 days ahead: Mix together cranberries and sugar in a bowl. Cover with plastic wrap and refrigerate. In a separate bowl, dissolve gelatin in hot water. Add 1 cup reserved pineapple syrup. Mix well, refrigerate, and chill until partially set, about 1 hour. When gelatin is partially set, add cranberry mixture, 1 cup of crushed pineapple, celery, and walnuts. Pour into a mold that has been lightly coated with cooking spray. Refrigerate and chill until firm.

Thanksgiving/Christmas Day: Unmold salad on a large plate. Garnish with Frosted Grapes, if desired (recipe below).