1. Grease a 12-hole muffin tin with butter. Then put it in the fridge.

2. Preheat your oven, preferably about 527°F (275°C).

3. Add the milk, water, cinnamon stick, vanilla bean, sugar and lemon rind to a saucepan. Place it over medium heat. Simmer the milk until the sugar has dissolved. Then take the pan off the heat. Let the ingredients infuse for 5 minutes.

4. Discard the rind, vanilla and cinnamon.

5. Add the egg yolks to a large mixing bowl and whisk until pale and creamy.

6. Then add a tablespoon of warm milk to the egg yolks (make sure it's not piping hot) and whisk vigorously. Keep adding a couple of other separate tablespoons of milk and whisk in between. Then slowly add the remaining warm milk to the bowl. Keep beating the eggs.

7. Now add the custard mixture to a clean saucepan and place it over very low heat. Keep stirring gently but constantly with a spatula. Don’t let the custard burn.

8. Be patient. The custard needs quite a few minutes to thicken. Don’t turn the heat higher to speed things up or it can split. As soon as the custard has thickened to the consistency of double cream, remove it from the heat and cover the surface with cling film.

9. Cut the puff pastry sheet into 12 discs and place them in the buttered muffing tin. Divide the custard over the tart case.

10. Carefully put the tray in the hot oven. Bake the pasteis for about 10 to 14 minutes until the custard is caramelised on top.

11. Then remove the tarts. Sprinkle with icing sugar and cinnamon. Serve lukewarm.