You'll need 500g puff pastry. Grease lined-muffins cups with butter. Cut little slices and line the cups with it with the help of your thumbs. Leave it aside.
Mix 2,5dl cream with 4 yolks, 1 tea spoon of flower and 100g sugar. (To add some taste, you may want to dip in the mixture lemon zest and a cinnamon stick which you must take off in the end).
Simmer it until it starts boiling, always mixing. When it gets warm, pour the custard in the lined-muffins cups and take it to the oven, pre-heaten at 200ºC (~390F), for about 15-20 minutes.
Take the tarts off the molds once they're cold and serve it that way or powder some cinnamon and powder sugar.
