Soften gelatin in cold water and set aside.
Mix egg yolks, lemon juice, salt and 1/2 cup sugar.
Cook in double boiler until thickened. I tested this by dipping a spoon in the pan and if the mixture coated the spoon it was ready.
Stir in gelatin, lemon peel, and lemon extract with a whisk. Set aside.
Empty the boiling water out of the double boiler and replace with water and ice so you can set the bowl of gelatin mixture down into the ice water bath to cool the mixture down.
While the gelatin is cooling, using an electric hand mixer beat egg whites until soft peaks form. Gradually beat in remaining 1/2 cup of sugar and beat until stiff.
In a separate bowl whip the whipping cream.
Fold egg whites into the gelatin custard as it begins to congeal, then add in the whipped cream. Don't rush, and gently fold everything in using a spatula.
Pour into custard cups and refrigerate overnight.
Unmold and serve with a sauce of apricots pureed in the blender and sweetened with sugar to taste.