01 -
On a lightly floured surface, roll the thawed puff pastry sheet into a thin rectangle. Starting from a short edge, roll the pastry tightly into a log. Slice the log evenly into 12 pieces.
02 -
Place each dough piece cut-side down into the well of a standard muffin tin. Gently press and stretch the pastry with your thumbs to evenly line the bottom and sides of each cup.
03 -
In a medium saucepan, combine the granulated sugar, all-purpose flour, and a small splash of milk. Whisk until a smooth paste forms. Add the remaining milk, cinnamon stick, and lemon peel. Place over medium heat, whisking constantly until the mixture just begins to simmer and thickens.
04 -
Remove saucepan from heat and allow the mixture to steep for 10 minutes. Meanwhile, in a separate bowl, whisk the egg yolks until smooth.
05 -
Discard the cinnamon stick and lemon peel. Gradually whisk the warm milk mixture into the egg yolks. Pour mixture through a fine-mesh sieve to ensure a smooth custard. Allow to cool slightly.
06 -
Set oven rack in lower middle position and preheat oven to 500°F, or as high as safely permitted.
07 -
Pour the custard into each pastry shell, filling approximately three-quarters full. Bake for 12 to 15 minutes, or until the custard puffs and the tops develop brown blisters and slight charring.
08 -
Allow pastries to cool in their tin for 5 minutes, then transfer to a wire rack to cool further. Optionally, dust with ground cinnamon and powdered sugar before serving.