Dice the vegetables (excluding the peas) to small-medium cubes. Braise them 5-8 min., then add 2 pinches savory and a little black pepper. Remove from the heat, add a little salt and stir.
Pour the mince in a bowl and start adding the vegetables little by little, stir well (with your hands or with a stirrer). Beat the egg lightly in a bowl, pour 1/2 of it into the mince.
Lay out the puff pastry in a rectangle. Pour the mince along its length, form it like a stump. Smear the sides of the puff pastry with a little of the remaining egg. Wrap well with puff pastry and transfer to a tray laid out with baking paper.
Make several holes along its length with a fork so that the steam can escape and make stripes along the puff pastry with a knife. Smear everything with the remaining egg and sprinkle with a little salt.
You can arrange more potatoes around the roll, oiling and salting them lightly. Bake at 356°F (180 °C) for 40 min.
If you don't want to crisp the crust of the roll you can cover it with foil once it obtains the desired color.