The key to perfect pelmeni is a very thin dough and a juicy filling. Cold water or crushed ice is traditionally added to the filling to keep the meat moist during cooking.
A special mould (pelmennitsa) can be used to make pelmeni, but for home cooking, cutting out circles from the dough is sufficient. They are excellent served immediately after boiling, or sautéed after cooling.
In a large bowl, mix the flour, salt, and egg. Gradually pour in the cold water and knead until a firm but elastic dough forms. Knead on a floured surface for about 5-10 minutes.
Wrap the dough in plastic wrap and let it rest at room temperature for at least 30 minutes.
In a large bowl, mix the ground meat, chopped onion, minced garlic, salt, and black pepper.
Add cold water/crushed ice. Mix the filling thoroughly by hand until it is homogeneous and juicy. The filling must be juicy for the pelmeni to be flavourful.
Divide the dough into several portions. Roll out each portion into a very thin sheet (about 1-2 mm).
Cut out circles with a diameter of 4-5 cm (for example, using a glass). Reroll any leftover dough.
Place a small teaspoon of filling in the centre of each circle. Fold the dough in half into a crescent shape and firmly press the edges. Then join the two ends of the crescent to create an 'ear' or 'ring' shape.
In a large pot, bring a sufficient amount of salted water to a boil (you can also add a bay leaf).
Add the pelmeni to the boiling water (do not cook too many at once) and stir gently to prevent them from sticking to the bottom. Once they float to the surface, boil them for another 5-7 minutes until the dough is cooked and the meat is done.
Remove the cooked pelmeni with a slotted spoon, drizzle with a little melted butter, and stir. Serve hot with a spoon of sour cream, a few drops of vinegar, and sprinkled with fresh dill/parsley.