Remember to make a chicken-free version for the vegetarians.

For the Chicken Kotleti:
Prepare the meat mixture for the kotleti. Grate the onions
Soak the bread in the milk until soft. Pulse in the food processor. You can also puree the onions in the food processor or use a box grater. Add to the ground chicken.
Add the egg, sour cream, salt and pepper. Mix to combine. The meat mixture will be very soft. Set is aside.
For the Mushroom Stuffing:
Chop the fresh mushrooms into a small dice. Mince the shallot.
In a small bowl, place the dry mushrooms and cover with water. Cover with plastic wrap, poke a few holes in it and microwave for a few minutes until the mushrooms are softened. Drain. Mince the dry mushrooms.
Melt the butter in a skillet. Add the shallot, season with salt and pepper. Cook for about 3 minutes.
Add the mushrooms. Season with salt and pepper. Cook for about 7 minutes until the mushrooms are softened, and all the liquid is evaporated. Set aside the mushroom stuffing.
To assemble and cook:
Use damp/moistened hands to shape the kotleti, otherwise they will be too soft to handle. Keep moistening your hands every time you make another kotleta.
Take a portion of meat, form it into a meatball and make an indentation in the center. Place a heaping teaspoon of mushroom filling into the indentation. Cover the filling with the meat on the sides of the kotleta and shape into an oval.
Dredge the kotleta in the flour, brushing off the excess. Repeat with the remaining meat mixture and the mushroom stuffing. You should have about 16 kotleti.
Heat 1 Tablespoon of oil in a nonstick skillet on medium heat. Add the kotleti and cook until golden on both sides, approximately 3-5 minutes per side.