Preheat the oven to 230°C.
Boil 250ml water with sugar, cinnamon, and lemon rind, then simmer for 3 minutes and cool.
Mix plain flour and cornflour in a bowl with a small amount of milk.
Bring the remaining milk to a boil in a saucepan over low heat.
Whisk the boiled milk into the flour mixture until smooth.
Whisk the cooled sugar syrup into the milk and flour mixture.
Stir in the egg yolks, whole egg, and vanilla seeds.
Roll the pastry into a 50x30cm rectangle with a 1mm thickness.
Roll the pastry tightly lengthwise while brushing with water and cut into 2cm discs.
Press the pastry discs into muffin tin holes using a wet thumb.
Fill the pastry cases almost to the top with custard.
Bake for 20 minutes and cool for 10 minutes before serving.