Split the vanilla pod lengthways and heat with in milk in a saucepan.
Mix the flour, sugar and salt in a bowl. When the milk comes to a boil, remove the saucepan from the heat, take out the vanilla pod and scrape any remaining seeds into the milk. Add this preparation to the flour, sugar and salt mixture.
Add 4 egg yolks and 1 whole egg, along with 3 tbsp of lemon juice. Mix the batter vigorously.
Place the puff pastry into the small “pastéis de nata” tins and put a tablespoon of the mixture into each one.
Bake in the oven at approximately 200°C/210°C (gas mark 7) for about 10 mins.