I first learned how to make these a few years ago when the recipe was delivered through my door in my Spice Box from The Spicery. I'm going to dedicate a whole post to this wonderful company as they have completely broadened my cooking horizons!These little tarts are a favorite of my husbands and I made two batches of them for his godsons' naming ceremony this weekend. When I checked back at the end of the buffet there was not one left!
It is believed that these tarts were originally made before the 18thC by Catholic monks at the Jeronimos Monastery at a time when the convents and monasteries produced huge quantities of eggs as the egg whites were used for starching clothes (such as the nun's habits) and in wineries. There was a large quantity of egg yolk left over and so the monks and nun's invented these sweet pastries as a way to use up the leftovers! For 12 tarts you will need:
300 ml Jersey milk (or really good quality whole milk if you can't get Jersey)
4 medium eggs
130g caster sugar
15g cornflower
2 sheets ready rolled puff pastry (make your own if you really want to impress!)
2 cinnamon quills
1 bourbon vanilla pod (or 1 tbs vanilla bean paste)
1 tsp ground cinnamon
A muffin or yorkshire pudding tin
A pastry cutter
Pre-heat the oven to 220*C / gas mark 9
Grease your muffin tray
Cut the pastry into rounds, slightly larger than the diameter of the moulds and press the pastry to cover the sides and the base
Pour the milk into a saucepan and add the freshly scraped vanilla seeds and the empty pod if you are not using paste. Note here - I recently discovered vanilla bean paste. It's pricey at £7 a bottle, but there are a huge amount of servings in it, with 1 tbsp being the equivalent of 1 vanilla pod. Seeing as a vanilla pod is about £2 these days a bottle of this stuff is far more economical if you use them a lot! DO NOT use vanilla essence or extract, it will not have the same flavour!
Break the cinnamon quills into small pieces and add them to the milk and vanilla. Add the sugar and gently heat the whole lot to dissolve the sugar. The moment it starts to boil take it off the heat and leave it to cool.
Put the cornflower into a jug and strain in a splash of the milk mixture to make a really smooth paste. Strain in the rest of the milk, stirring continuously (it is sometimes easier to strain the milk first and then add it to the cornflower if like me you struggle to juggle a jug, a spoon, a sieve and a saucepan with only two hands!)Separate the eggs and beat the yolks. Hang onto the whites if you fancy starching your nun's habit (or making pavlova).
Pour the milk and cornflower mixture into the egg yolks, stirring continuously. There should be no lumps! Fill the pastry cases to just below the top and carefully place in the top of the oven.
Bake for 12-14 minutes until the pastry around the top is crisp and brown. Sprinkle the ground cinnamon over the top. 
They will keep for about 2 days...if they last that long!
I had a lot of pastry and custard left over after making my batches. I thought I would give a giant version of these tarts a go. It was an unmitigated disaster. The custard caramalised and burnt, the edges of the pastry caught and blackened while the middle layers of the pastry were still raw. I'm determined to crack it though! 
