Whisk the cornstarch and milk together in a small, non-reactive saucepan. Add the lime zest. Heat for about 10 minutes on a medium low heat, stirring frequently. Allow to simmer but do not boil, until the mixture thickens noticeably. Set aside to cool.
Preheat the oven to 350 F.
Beat the egg and egg yolk together. Strain the Clabber Girl Corn Starch mixture and add to the eggs along with the sugar, flour and lime juice. Whisk until smooth and creamy.
Divide evenly among 4 - 6 individual pudding cups, place on a baking sheet and bake for about 20 to 24 minutes to set.
Allow to cool for about 20 minutes and slip cookies down the side of the pudding cups*, cover with plastic and refrigerate for 1 to 2 hours.
* For a crisp topping, crush the cookies into crumbs and divide over the top of the pudding cups just before serving.