Make the dough: in a large bowl combine All-Purpose Flour with a pinch of Salt. Make a well, add a beaten Egg and about 1/2 cup warm Water, then mix until a shaggy dough forms. Knead on a lightly floured surface until smooth and elastic (about 8–10 minutes), cover and let rest 30 minutes.
Prepare the filling: in a bowl mix together Ground Pork and Ground Beef with finely chopped Onion and freshly ground Ground Black Pepper. Add a little Salt to taste and mix until combined and slightly tacky — taste a small fried pinch and adjust seasoning if needed.
Shape the pelmeni: roll the rested dough thin (about 1.5–2 mm) and cut rounds with a 6–7 cm cutter. Place about a teaspoon of filling in the center of each round, fold into a half-moon, press edges firmly to seal, then bring the two corners together and pinch to form the traditional pelmeni shape. Keep finished pelmeni on a lightly floured tray.
Bring a large pot of Water to a vigorous boil, add a generous pinch of Salt, a Bay Leaf and a few Black Peppercorn.
Cook the pelmeni: drop the dumplings into the boiling water in batches so they don’t stick. Stir gently so they don’t cling to the bottom. When they float, cook for an additional 4–6 minutes until cooked through.
Remove the pelmeni with a slotted spoon and transfer to serving plates. Dress with a spoonful of Sour Cream, a knob of melted Unsalted Butter and, if you like, a small splash of White Vinegar for brightness. Finish with freshly cracked Black Pepper to taste.
Optional: for a crisped finish, sauté boiled pelmeni briefly in a hot skillet with a little Unsalted Butter until golden on one side before serving.
