In another bowl beat egg yolks well. Add sweetened condensed milk and continue beating. Slowly add key lime juice while beating. Fold egg whites into egg yolk mixture with spatula, mixture should be even. Pour into pie crust. Bake about 20 minutes or until just set. Cool completely before refrigerating. Refrigerate at least 2 hours before serving. Makes 6 slices. Top each with whipped cream. Keeps well for up to 3 days.