Cook over medium heat, stirring constantly, 12 to 15 minutes, until apples are slightly transparent and tender. Add one half the gelatine, stir until dissolved. Pour into pie shell. Chill. Combine Eagle Brand Sweetened Condensed Milk (Eagle Brand is milk and sugar, already cooked… blends instantly with other ingredients), lemon rind, lemon juice and egg yolks; stir until thickened.
Dissolve remaining gelatine over hot water; stir into mixture. Beat egg whites until stiff but not dry; fold into mixture. Pour over apple mixture. Chill until firm, about 2 to 3 hours. Garnish with whipped cream and reserved apple slices. (Makes one 9-inch pie.)