Use the pie dough to make 6 pastry shells. Bake thoroughly and set aside to cool.

Place the lime juice, 1 cup of water, and the sugar in a saucepan and bring to a boil over high heat. Meanwhile, in a mixing bowl, dissolve the cornstarch in ½ cup water. Whisk in the egg yolks. Slowly pour 1 cup of the boiling lime syrup into the yolk mixture and blend it thoroughly. Pour the mixture back into the saucepan and bring to a boil, stirring constantly. Remove from the heat, add the butter and mix.

Pour into the pre-baked tart shells and let set for about 30 minutes before serving.