Place a saucepan over medium heat and pour in the heavy cream. Add the broken cinnamon stick and a couple of pieces of lemon peel (without any white pith). Bring to a boil, then reduce the heat to low and let it simmer for 4 minutes. Meanwhile, in a large bowl, combine the egg yolks and milk. Whisk until blended, then add the cornstarch and whisk until smooth with no lumps. Add the sugar and continue whisking until almost dissolved. Strain the infused cream and pour it into the egg mixture, stirring until fully combined. Let cool to room temperature.

Grease the tart molds lightly with butter and set aside. Roll out the puff pastry sheets and tightly roll each one into a cylinder. Cut into pieces about 1 1/4 inches (3 cm) thick. Place each piece in a mold and press from the center outward to cover the bottom and sides with a thin layer of pastry. Once all the molds are lined, refrigerate them if the custard is still warm. Preheat the oven to 350°F (180°C) with convection, or 375°F (190°C) if you don't have convection.

Pour the cooled custard into a pitcher and fill the pastry shells, leaving a little space at the top. Bake at 350°F (180°C) with convection for 30 to 40 minutes, or until the pastry is golden and fully cooked. Remove from the oven and let cool—though they're even better slightly warm. Dust with ground cinnamon and powdered sugar to taste before serving. Enjoy! Give them a try, you'll love them.