Preheat oven to 200C/Gas 6

Spray the muffin tins with oil or brush with a little melted butter

Cut 24 circles from the puff pastry and line each section of the tin to form a pastry cup. Set to one side.

Whisk the egg yolks and sugar together in a bowl and set to one side.

Pour the milk into a saucepan with the cinnamon and lemon zest. Split the vanilla pod, scrape out the seeds and add to the milk, along with the pod. Gently warm through until just about to boil. Remove the vanilla pod.

Slowly, start to pour the hot milk into the egg and sugar mix, whisking continuously so that the eggs don't scramble.

To make filling the pastry easier, pour the milk and egg mixture into a jug. Divide between the 24 tarts and place in the oven for 30 minutes. After this time check to see if they are set, if not, pop back in the oven for another 10 minutes, if they are starting to burn, you can turn the oven down slightly.

Best served warm.