To make dough, mix together flour and 1 teaspoon salt in a large bowl. Add egg and water; mix with a large wooden spoon until most of the flour is incorporated. Turn out onto a lightly floured work surface and knead by hand until dough is smooth and pliable. Wrap dough in plastic and let rest for 15 minutes to 1 hour.

Combine beef, pork, onions, 3/4 teaspoon salt and pepper in a large bowl; mix well. Refrigerate until needed.

Unwrap dough and divide into 2 to 3 parts, covering unused dough to prevent it from drying out. On a lightly floured work surface, roll out dough about 1-millimeter thick. Using a 2-inch round cookie cutter, cut out circles of dough. Gather up dough scraps, press into a ball, roll out and reuse.

Place about 1/2 teaspoon filling in the center of each circle; pinch edges of dough together to form a half-moon shape, starting at the ends and moving towards the middle. Fold dumpling in the middle, bring the ends together, overlap and seal. The resulting shape should resemble a cloche hat.

Cook pelmeni immediately or freeze for later use. To freeze, place pelmeni on a baking sheet dusted with flour and freeze until hard, then transfer to a sealable bag.

To cook pelmeni, bring a large pot of salted water to a boil. Add pelmeni and bay leaves; stir carefully and return to a boil. Boil for 5 minutes, then remove pelmeni with a slotted spoon or ladle into bowls with some of the cooking water, which has now become a light broth. Serve immediately, garnished with your choice of toppings.