On the Internet, you will find a lot of minced chicken recipes. This is a mockery, not recipes - after all, cue balls are named so because the meat needs to be beaten, and not scrolled!
For meatballs, beat the chicken fillet with a hammer until minced or chop with a heavy chef's knife as finely as possible.
Crush, peel and chop the garlic. Mix chopped fillet with garlic and starch, salt and pepper.
Beat the egg with yolks and sour cream, add to the minced meat and knead thoroughly. Place in refrigerator for 30 minutes.
Finely chop the mushrooms for the sauce and finely chop the onion. Melt the butter in a heavy bottomed saucepan, add the onion and sauté over medium heat for 5 minutes. Add mushrooms, increase heat to high, cook 5 minutes.
Sprinkle the mushrooms with onions with flour, mix, simmer for 2 minutes. Pour in the milk, stir thoroughly, simmer until thickened, 3-4 minutes.
From minced meat, lubricating your hands with oil, blind small round meatballs. Fry them in a pan on both sides, 4-5 minutes each. Serve with sauce.