Orpha Jane Austin's 24 Hour Salad

Why I Love This Recipe
Ingredients You'll Need
1 lb small marshmallows
1 1/2 cup white grapes
1 cup walnuts or pecans
1 lg can diced pineapple (drain, but save juice)
Dressing
4 egg yolks
1/2 cup sugar
Juice of two lemons
Cool Whip
Directions
Mix dressing ingredients together and cook in double boiler until thick. Let cool, then add whip cream. Combine everything with dressing lightly. Let stand. Chill 24 hours.
The ingredients' list mentions saving pineapple juice, but it is not mentioned again in the recipe. I am not sure if that was an oversight and it should be used in the dressing or if this recipe just comes from the era of saving and using everything.