Russian
Mix flour, egg, cold water and salt into a firm dough, knead 8 minutes until smooth, then rest covered 30 minutes.
Combine pork, beef, grated onion, garlic, salt, pepper and 2 tbsp cold water into a soft, well-mixed filling.
Roll the dough thin and cut out 6 cm rounds.
Place a small ball of filling on each round, fold into a half-moon and seal, then pull the two corners together and pinch to form the classic ring.
Bring a large pot of salted water to a rolling boil and drop in the pelmeni in batches.
Cook 4 to 5 minutes after they float to the surface, then lift out with a slotted spoon.
Toss with melted butter and serve hot with sour cream.