Pastel de Nata (Portuguese Custard Tart)

Method

1. 1Put the sugar, water, cinnamon stick and lemon peel in a small pan and bring to a boil. Cook to 100-104C without stirring once, about three minutes; stirring makes the syrup crystallise.
2. 2Whisk the flour and salt with a splash of the cold milk until smooth, add the rest of the milk and cook over medium heat, whisking, for five minutes until it thickens.
3. 3Strain the hot syrup into the hot milk base in a thin stream while whisking hard. Take out the cinnamon and peel and let the mixture cool for ten minutes.
4. 4Whisk in the egg yolks one at a time, then pass the custard through a sieve into a jug. It stays thin and pourable, which is correct — a thick custard sets rubbery.
5. 5Roll the puff pastry into a tight log, chill it for 20 minutes and cut it into 12 rounds.
6. 6Set each round cut side down in a muffin tin. Dip your thumbs in cold water and press the pastry up the sides so it stands a little above the rim.
7. 7Fill each shell three quarters full and bake on the lowest shelf at the highest setting your oven has, 250-290C, for 12 to 15 minutes until the pastry is golden and the custard is spotted dark. Cool five minutes in the tin, then dust with cinnamon.