Step 1

Set up a double boiler and combine the eggs, sugar and vinegar in the top pan (be careful not to let any boiling water leak into the mixture).

Step 2

Stir the mixture constantly until it thickens then set it aside and let it cool.

Step 3

Beat the whipping cream until soft peaks form.

Step 4

Combine the grapes and marshmallows in a large bowl.

Step 5

In a separate bowl, mix together the pineapple and the egg mixture and then gently fold in the whipped cream.

Step 6

Now gently fold the whipped cream mixture into to the bowl of grapes and marshmallows.

Step 7

Allow the salad to chill for 24 hours before serving.