How to make
Cut the thawed puff pastry into squares. Grind the walnuts finely. To them add the egg and sugar.
Stir well until the walnuts start to look like wet sand. Place a little of the walnut mixture in 1 corner of the squares and fold them into triangles.
Press slightly so that they don't open up during baking. Bake the triangular puff pastries in a preheated 360°F (180 °C) oven until swollen and golden (about 15-20 min). For the syrup, put the water on a moderate stove and add the sugar.
Once boiling, leave it for 20 min. to cook. Take the sugar syrup off the stove and add the vanilla. Syrup the cooled triangular puff pastries with the slightly cooled syrup. Don't pour boiling syrup over them!