Place the puff pastry over a table dusted with flour. Dust the pastry with a little more flour and roll out the pastry into a rectangle shape with a rolling pin. Roll the pastry from one end to the other and cut in round slices with 4 centimeters / (1 1/2 inches). Put the slices within the muffin pans and press the center of the pastry with fingers until fill completely the muffin pans, set aside.
In a bowl, dissolve the corn starch in 50 ml / (3 1/3 tablespoons) milk.
In a saucepan, pour the remaining milk, lemon peel, cinnamon stick, the dissolved corn starch and sugar. Stir and bring to low heat, stirring occasionally. When starts boiling, remove the lemon peel and the cinnamon stick (reserve both). Turn off the heat and add the egg yolks one by one, stirring constantly. Add the lemon peel and the cinnamon stick and place back over low heat until obtain a creamy mixture, about 3 to 4 minutes, stirring occasionally.
Meanwhile, preheat the oven to 180ºC / (350ºF).
Turn off the heat, remove the lemon peel and the cinnamon stick and pour the cream in the muffin pans. Bake for about 30 minutes.
Remove from oven, unmold and let cool. Sprinkle with cinnamon and powdered sugar and serve.