Put the cornstarch and water into a small saucepan and mix to dissolve the cornstarch.
Add the lemon juice and acesulfame-K.
Cook gently, stirring constantly until the mixture thickens.
In another pan, heat the egg substitute.
Spoon some of the lemon mixture into the eggs.
Now combine in the rest of the lemon mixture and the vanilla extract.
Cook over low heat for a minute or two.