Whisk egg, salt and 1 teaspoon oil in a cup. Add water and flour and knead until you have smooth and elastic dough, about 5 to 7 minutes. You can do this in your food processor with the dough blade. Turn it off when the mixture is forming a ball. Cover with a kitchen towel and let rest for 30 minutes.
Combine all the ingredients, and mix thoroughly by hand or using a fork. You can also put it through the meat grinder but don’t process in the blender or food processor, unless you have a special setting for meat.
Roll out the dough 2mm thick, cut out rounds 6 to 7cm in diametre (I use a wine glass for this). Keep the rest of the mixture covered with a tea towel to keep it soft and pliable. Place ½ to 1 teaspoon of filling on one side of the circle. Seal the edge using fingers, forming a crescent. Join the ends and pinch them together.
Roll out dough 3mm thick, on a table dusted with flour. You should end up with a circle slightly bigger than the mould. Place rolled out dough onto the mould with the floured side down (the side looking up should be sticky). Place about 1 teaspoon filling into every section. Cover with another dough layer and sprinkle with flour on top. Roll over the top with your rolling pin, until pelmeni start popping out of the mould. Gather the rest of the dough, add to it a new portion, and roll out again, repeating the process until all the dough is used up.
Arrange the prepared pelmeni on a baking tray lightly dusted with flour. Place in a freezer for 30 minutes (to prevent sticking), then store in a sealable plastic bag or a container with a tight fitting lid.
Drop small batches of frozen pelmeni into simmering and slightly salted water, stir, so that pelmeni do not stick to each other. Cook until pelmeni float, then boil for additional 5 to 7 minutes and remove onto plate using slotted spoon. Or, fry frozen pelmeni in melted butter (you can also add bacon) – like pierogi. Pelmeni are usually served with soured cream or vinegar.