Pastel de nata pie

1. Beat the egg yolks with an electric mixer. Reserve. Dissolve the cornstarch in a spoon in 50 ml of milk.
2. In a saucepan place the sugar together with the dissolved flour, the remaining milk, the lemon peel and the cinnamon stick. Bring to a low heat and stir with a wooden spoon until slightly creamy.
3. Remove the pan from the heat for a moment and wrap the egg yolks in the mixture, stirring constantly. Put the pan back on the stove and stir with a spoon until the cream thickens a little more. (note: the cream should not be too liquid or too solid)
4. Turn off the heat and remove the lemon peel and cinnamon stick.
5. Line a pie dish with the puff pastry and prick the bottom with a fork. Pour the cream on top of the dough and place it in the preheated oven at 180ºC for about 25 to 30 minutes until the top is toasted.
6. Remove from the oven, unmold onto a plate and sprinkle with ground cinnamon.