1 tbsp. unflavored gelatin
1/2 c. water
4 egg yolks, saving the whites for later
1 c. sugar or 1/2 c. sugar & sugar substitute equivalent for 1/2 c. of sugar, suitable for baking
1/2 c. key lime juice
1/2 tsp. salt
2 tbsp. bitters
Lime zest from 1 lime
Baked pie crust

In a small bowl, combine the gelatin and water until gelatin is dissolved; put this and the rest of the ingredients, except the egg whites, into a double boiler. Cook until hot. Remove from the heat and add the stiffly beaten egg whites, by folding in. Pour this into your baked pie crust and chill until firm.