Mix 65 ml of the evaporated milk with the egg, egg yolks, flour, cornflour and sugar.
Heat remaining milk, and when it comes to the boil, beat in the egg mixture.
Reduce heat immediately and carry on beating until the mixture thickens.
Remove from the heat and stir in the vanilla essence.
Chill to room temperature and fill the tartlet shells with the filling.
Sweeten the fruit to taste with extra castor sugar.
Allow to stand for 30 minutes.
To make the tartlet shells
Sift 500 ml flour, 5 ml salt and 20 ml castor sugar together. Rub 175 g cold butter into the flour mixture into the flour mixture until it resembles breadcrumbs. Whisk 1 egg, 2 ml vinegar and 15 ml cold water together and add. Lightly mix to form a dough.Wrap in clingfilm and refrigerate for at least two hours. Roll out and line tartlet tins. Bake blind for 15 to 20 minutes at 180 °C or until shells are lightly browned and done.
Leave to cool completely before removing from the tins.