Grate the cheese on a fine grater.
Cut the mushrooms into small cubes.
Finely chop the onion.
Fry the onions and mushrooms in vegetable oil for 5 minutes.
Divide the chicken in half lengthwise. Using a meat mallet or the blunt side of a knife, punch each piece of fillet to create 3-4 mm thick pieces. Season with salt and pepper.
Place the filling on each half of the medallion: fried mushrooms with onions and grated cheese.
Fold the pieces of meat in half so that the filling is inside. They should look like chicken "pies".
Let's start breading the brizol. Roll each "pie" in flour, then dip it in a raw egg and roll it in breadcrumbs.
Cook the brizol with vegetable oil over low heat for 5 minutes on each side.
Before serving, garnish the dish with fresh herbs and cherry tomatoes. Enjoy.