Prepare the fish fillet. Peel the onions.
Cut the fish fillet into pieces and pass it through a meat grinder, also pass the onion. Add eggs, salt to the resulting minced meat and mix everything well.
Chop the second onion and mushrooms. Simmer them in a frying pan, pouring cream, until the cream evaporates. Place half of the minced fish on a sheet of foil greased with vegetable oil and smooth it out. Place the mushroom and onion filling on top so that the filling is in the middle of the minced meat layer. Spread the remaining minced meat on top.
Wrap the roll in foil. Place it in a baking dish and pour some water into the pan. Place the roll in the oven for 40 minutes.
Cut the finished roll into portions and decorate it with herbs. To make the dish look elegant and complete, you can serve pieces of roll with cream cheese and fresh herbs.