Lemon Chiffon Pie

Step 1
Pour cold water into a bowl; add gelatin and let stand until softened, about 5 minutes.

Step 2
Beat 1/2 cup of sugar, egg yolks, lemon juice, and salt together in a bowl until smooth. Cook in the top of a double boiler, stirring constantly, until it is the consistency of custard. Add grated lemon zest and softened gelatin and stir thoroughly; set aside to thicken and cool, about 10 to 15 minutes.

Step 3
Beat egg whites in a glass, metal, or ceramic bowl until foamy. Gradually add remaining 1/2 cup of sugar, continuing to beat until soft peaks form; fold egg whites into cooled custard mixture.

Step 4
Pour filling into prepared pie shell and chill in refrigerator until firm, at least 2 hours. Garnish with sweetened whipped cream if desired.