Place a layer of pound cake inside the ring mold. If necessary, trim the cake layer to fit. Set all aside. Store in the refrigerator until ready to use. Let stand for about 5 minutes to allow the gelatin to soften and hydrate.
Cold water hydrates the gelatin without letting it absorb too much liquid.
Remove the gelatin from the bowl and squeeze out the excess water with your hands. Let the gelatin bloom until it has absorbed all the water, about 1 minute. Place the egg whites in a medium-sized mixing bowl. Remove the mixture from the heat. Use an electric mixer set on medium speed to whip the egg whites for about 5 seconds.