In a medium saucepan add water, sugar, lemon peel and cinnamon sticks and place over medium heat. Cook, without stirring, until the mixture gets to 220°F (100°C). Remove from heat and set aside.
In another medium saucepan add the flour and salt and gradually mix in the milk. Place over medium-low heat until thickened, whisking continuously.
Remove from heat and add vanilla extract. Strain the sugar syrup over the milk mixture. Whisk to combine.
Let cool slightly. Gradually add egg yolks and mix to combine. Strain the mixture into a jug. Set aside until you prepare the pastry cups.
Preheat the oven to 500F (260C). Slightly grease a 12 cavity muffin pan.
Divide the dough pieces into the muffin pan. Using wet fingers, gently press the dough onto the bottom and sides of each muffin cup.
If the dough softened too much, refrigerate the pan for about 10-15 minutes.
Fill each cup with prepared custard, ¾ full.
Bake for 10-13 minutes, until the edges are browned and custard is puffed and blackened in spots.
Cool slightly in the pan, and then transfer to a cooling rack.
Dust with powdered sugar and cinnamon powder and serve slightly warm. Enjoy!