Preheat oven to 240º C.
In a saucepan, place the milk, lemon peel and cinnamon sticks. Bring to the heat until it boils and turn off.
In a bowl, mix sugar and flour. Add the mixture to the milk, while still hot, stirring well with the help of a wire whisk (fouet).
Remove the lemon peel and cinnamon sticks and let it cool for 10 minutes.
Add whole eggs and yolks. Stir with the sticks until it forms a smooth cream. Bring to the heat again, stirring constantly until it thickens.
Roll the puff pastry into a cylinder and cut into 3 cm slices each. With the help of your wet thumbs, line small metal shapes, spreading the dough well to the edge.
Pour the filling into the molds and bake for 15 minutes, or until golden.
Decorate with powdered cinnamon if you prefer and serve while still hot.