Working on this recipe
.Bring the sugar, cinnamon
(I've replaced cinnamon for lemon, just to flavour the syrup, I prefer the fresh cinnamon taste only on the outside, not in the custard itself), and water to a boil in a small saucepan and cook until an instant-read thermometer registers 220°F (100°C). Do not stir.
Meanwhile, in another small saucepan, scald the remaining 1 cup milk. In a medium bowl, whisk the flour and 1/4 cup of the milk until smooth. (Instead of 3 Tsp wheat flour I've used 2 Tsp wheat flour + 1 Tsp corn starch)
Whisk the flour mixture into the hot milk.
Pour the sugar syrup in a thin stream into the hot-milk-and-flour mixture, whisking briskly.
Set aside on a cold bowl.
Don't forget the yolks should be stired while it's still warm, but I'll go there further.
I've used frozen puff pastry, I didn't make mine.
Overlay the several sheets of puff pastry, rubbing some soft unsalted butter in between them. Make them double their length and then roll then.
Cut it 12 similar pieces.
Put each slice of the puff pastry roll in a previously greased (with unsalted butter) mini-muffin pan and let it rest for 2 hours.Have a small cup of water nearby. Dip your thumbs into the water, then straight down into the middle of the dough spiral. Flatten it against the bottom of the cup to a thickness of about 1/8 inch, then smooth the dough up the sides and create a raised lip about 1/8 inch above the pan. The pastry sides should be thinner than the bottom.
Fill each cup 3/4 full with the slightly warm custard. Bake until the edges of the dough are frilled and brown, about 8 to 9 minutes.
(I'll say 15 to 20 minutes at 250ºC)
And this is what you'll get :
I did like the final result, altough it is a bit too sweet. But the custard cooked very well and looked lovely.