How to Make It
Preheat oven to 300°F. Place the walnuts on a baking sheet. Bake in preheated oven until golden brown, 10 minutes. Set aside. Toss chopped cranberries with sugar. Let stand while preparing salad.
Dissolve the gelatin in boiling water, then stir in the lemon juice and salt. Drain the pineapple and reserve syrup. Pour reserved syrup into gelatin mixture and cool thoroughly. Stir in the carbonated beverage and chill until thickened.
Stir the cranberry mixture, pineapple, celery, and walnuts into gelatin mixture. Spoon into a lightly greased (with cooking spray) 6-cup mold and chill until set, 4 hours. Unmold onto salad greens.