1) Place the puff pastry on a clean surface. With a metal serving ring, cup or glass cut out 14 large circles, 3 inches (7,5 cm) in diameter. Leave 2 of the circles intact and then cut out the middle of the remaining 12 circles, creating rings.
2) Then remove the middle circle. Prick holes in the 2 intact circles using a fork.
3) Once that's done, assemble the vol au vent: place the 2 intact pastry circles and the 14 pastry rings on a clean chopping board. Brush them all with a little beaten egg yolk.
4) Then start building up the vol au vent: place the pastry ring on top of the circle. Keep on doing that until you have a nice little stack of puff pastry.
5) You can also use the mini circles you cut out and then brush them with the egg yolk if you don't want to throw them away.
6) Place the 2 pastry towers (and the small circles) on a baking tray lined with baking paper. Bake them in a preheated oven at 374°F (190°C) for 25 to 30 minutes until golden and crisp. Keep an eye on them and cover with tinfoil if necessary. Then remove them from the hot oven and serve with your favorite filling!