Sunny Silver Pie

In a bowl, pour gelatin into cold water and let sit. Separate eggs whites from yolks. Place yolks, lemon juice, zest, a half cup of sugar, and salt in a round-bottom glass or enamel bowl. Set bowl in a larger pot of boiling water. Whip with an electric mixer until mixture becomes firm and creamy. Reduce heat and fold in gelatin. In a bowl, beat egg whites until stiff and combine with remaining half cup of sugar. Fold whites into yolk mixture. Pour filling into pie shell and chill for two hours. Whip cream until stiff and spread over top of pie before serving.