Preheat the oven to 425 degrees
Bring 220 grams of sugar and 2/3 cup of water to simmering in a small saucepan over medium heat
Add 1/4 teaspoon of ground cinnamon and whisk while simmering to combine
Once the sugar has completely dissolved, remove from the heat and set aside
In a medium saucepan, bring 1 cup of whole milk and 2/3 cup of heavy cream to a light boil and remove from the heat and set aside
In a medium bowl, whisk together 5 egg yolks, 1 large whole egg, 1 tablespoon of vanilla extract and 1/4 cup of corn starch
Slowly add the hot milk mixture to the egg mixture, whisking constantly to avoid the eggs becoming too hot too quickly
Once the milk and eggs are fully combined, pour this mixture back into the medium saucepan and return the pan to medium heat
Whisk this mixture constantly over medium heat until it develops a pudding like texture and then remove it from the heat
Slowly add the dissolved sugar mixture, whisking constantly, until everything is fully incorporated and then set this aside
Roll the puff pastry out onto a lightly floured surface and divide into 12 equal portions
Press a portion of puff pastry into each cup of a standard 12 cup muffin pan
Fill each cup 2/3 of way full with the custard filling
Bake at 425 degrees for about 18 minutes or until the edges are golden brown and the custard feels set to the touch
Serve warm, dusted with confectioners sugar