Using a food processor or blender, mash or blend the strawberries. Combine with vanilla extract, half the sugar substitute and lemon juice. Set aside.

Beat the egg yolks until thick and lemon-colored and add to the fruit mixture.  Beat the egg whites along with the remaining sugar substitute.  Fold the fruit mixture into the beaten yolks.  Incorporate well and then mix into the beaten egg whites. Freeze in an airtight container.

For a fluffier sorbet, remove from the freezer before it gets completely firm. Mix with a hand mixer or in a food processor with knife blade, and return to the freezer. Repeat this 2-3 times. Let soften a few minutes before serving.