For the potato sacks with mushroom-cranberry filling, first peel the potato, boil until soft and allow to steam.
Cut the shallots into small cubes. Clean the mushrooms and fry them with the shallots in sunflower oil. Drain well.
Mash the potato and mix with the remaining ingredients for the filling. Season well with salt and pepper.
Cut the strudel dough into 10 x 10 cm squares. Brush each layer with egg and stack 2 squares on top of each other.
Butter a muffin tin and line each well with the strudel sheets. Put a tablespoon of filling in each, pull up the corners of the strudel dough and press together to form a little bag.
Brush the sacks with the remaining egg and bake in a preheated oven at 170 °C for about 15 minutes. Lift out of the mold.
Put the chives in boiling water for 30 seconds, then rinse with cold water. Tie a stitch around the strudel bags with the chive stalks and serve the potato bags with mushroom-cranberry filling immediately.