How to make
Prepare the confectionery cream by heating the milk with the sugar and vanilla sugar over medium heat.
Beat the egg and the yolk with the flour and a little more milk and pour it in a thin stream, while constantly stirring, to the milk. Continue stirring, until the cream thickens - about 4-5 minutes over low to medium heat.
Cover the finished cream with cling film, so that it does not form a crust and stick it tightly to its surface.
Put the round and very thin puff pastry crust into a 11″ (28 cm) diameter tart tin. Leave the edges sticking out or fold them over to form a thicker border.
Pierce the bottom of the dough with a fork, so that it does not rise during baking and put it in an oven heated to 390°F (200°C) to bake, but without it aquiring a golden brown color.
Remove it quickly and pour the cream in a thin and even layer over the semi-cooked dough. Sprinkle it with the brown sugar and place it back into the oven, until it becomes lightly golden on the edges.
When melted, the sugar will liquefy, but then it soaks into the cream and becomes very tasty.
After turning off the oven, leave the tart tin inside with the door open for 5-10 minutes.
Start with the walnuts by toasting them in a non greased pan, then chopping or grinding them.
Sprinkle them over the thin puff pastry tart.
You can serve this temptation while it is still slightly warm.
If you want your puff pastry tart to not be as fine and thin, you can prepare more cream and garnish it with different fresh seasonal fruit.