Make the Dough:

In a bowl, mix the flour and salt. Add the egg and water (or milk) and mix until it forms a dough. Knead the dough on a floured surface until it’s smooth. Cover it and let it rest for about 30 minutes.

Prepare the Filling:

Mash the boiled potatoes in a bowl. Add the caramelized onions and chopped bacon to the potatoes. Mix well and season with salt and pepper.

Roll Out the Dough:

Roll out the dough on a floured surface until it’s about 1/8 inch thick. Use a glass or cookie cutter to cut out circles from the dough.

Fill the Dough:

Place a spoonful of the filling in the center of each dough circle. Fold the dough over to make a half-moon shape and press the edges together to seal them. You can use a fork to press the edges to make sure they are sealed well.

Cook the Vareniki:

Bring a large pot of salted water to a boil. Carefully drop the vareniki into the boiling water. Cook them for about 3-5 minutes, or until they float to the top. Remove them with a slotted spoon.

Serve:

Serve the vareniki hot, topped with a dollop of sour cream, fried onions, or melted butter. Enjoy your delicious homemade vareniki!