For the strudel sacks with potatoes, Emmental and peas, first boil the potatoes in salted water until soft and mash them with a fork without liquid. Stir in the sour cream, Emmental and the peas, season with salt and pepper and finally fold in an egg.
Put the butter in a saucepan and let it become liquid. Cut 6 x 6 cm squares from the strudel dough. Butter one sheet of strudel dough and place a second one on top, brush with egg and place a small amount of potato mixture in the center. Fold the ends of the strudel sheet together.
Brush the sachets with butter and bake in a preheated oven at 160 °C for 20 minutes. Remove from the oven and serve the strudel sacks with potatoes, Emmental cheese and peas while they are still hot.