Fish dumplings with tuna

Источник фото: https://ru.123rf.com/profile_liudmilachernetska
Even those who don't like fish options may like tuna dumplings. Tuna has an original taste, close to meat.
For original fish dumplings with tuna, prepare the ingredients according to the recipe list.
Ингредиенты
For filling:
Tuna fillet - 400-500 g
Onion - 0.5-1 pcs.
For the test:
Flour – 300-350 g
Milk or water – 100 ml
Egg – 1 pc.
Sour cream or kefir – 1-1.5 tbsp.
Salt - 1 pinch
Vegetable oil - 1 tsp. (for hands)
Рецепт
1. For the dough, combine and mix all the ingredients together. The amount of flour may vary, depending on the properties of the flour from a particular manufacturer and the size of the egg.
2. To prevent the dough from sticking to your hands, grease them with vegetable oil. Knead the dough until elastic, cover, place in the refrigerator and start filling.
3. Minced tuna fillet with onions is easiest and most correct to prepare in a meat grinder, but it is also possible to use a blender or food processor. But it so happened that I had tuna, but I didn’t have the specified kitchen equipment or at least a rolling pin... Therefore, I suggest taking note of a way to simply chop the fish fillet with a knife and the onion too. Mix the onion with the tuna and the minced meat is ready. My version doesn't have anything else added, but you can add salt and/or pepper to your liking.
4. Roll out small portions of dough thinly. I use a small glass bottle, it's almost as convenient as using a rolling pin.
5. Cut the dough into round pieces. There was no mold or glass either; a glass sauce jar would do.
6. Place a suitable portion of minced meat (about 1 teaspoon) in the center of the dough piece and pinch the edges, giving it a traditional dumpling shape. Place the semi-finished products on a board sprinkled with flour.
7. Cook fish dumplings with tuna in the usual way. Place in boiling water with salt, peppercorns and bay leaf. After the dumplings boil and float, reduce the heat and cook for another three minutes.
8. Serve dumplings with tuna with fresh chopped herbs to taste, as well as with any sauces: sour cream, butter, ketchup, adjika, soy...