In a large mixing bowl, whisk together an egg, milk, water, salt, and sugar. Add half of the all-purpose flour and using a spatula, fold it in. Then add the rest of the flour and mix.
Transfer the dough to a counter and knead for about 7-10minutes, until the dough is soft and elastic. Wrap it with a plastic wrap and let it rest on the counter for about 40-50 minutes.
In another mixing bowl, add ground pork, ground beef, grated onion, salt and pepper. Using a spatula or your hands, mix everything until evenly combined.
When the dough is ready, knead it again until it’s soft and elastic, adding some more flour. Cut a piece of the dough (about an apple size) and roll it evenly until about ¼-inch thin.
Cut the circles from the dough using a glass or a special circles cutter. Put about 1 teaspoon of meat mixture in each circle and make the shape of the pelmeni. (you can watch my video tutorial)
When the pelmeni are ready, you can cook them right away or put them in the freezer. Whether you decide to cook them fresh or frozen, the technique and timing will be the same. It’s similar to cooking pasta.
Boil a large pot with water over high heat. When the water starts boiling, add frozen or freshly made pelmeni and stir, so they don’t stick together. Cook for about 10 minutes or until the dumplings start to float on top.
You can scoop them out of water with a strainer ladle or drain the liquid like you would do it for pasta.