Add the mushrooms and continue cooking until the liquid evaporates.
Then add the pre-cooked rice, salt and pepper to taste. Stir and remove from heat.
Cool slightly and add 100 grams of grated cheese and 3 tbsp sour cream. Stir everything again. The filling is ready.
Pour boiling water over the squid and immediately fill it with ice water.
Skin the squid by removing the chord and entrails. Cut off the squid tails carefully. You can leave them if you want, but I prefer to delete them.
Fill the squid carcasses with the filling, fasten the edges with a toothpick and place them in a baking dish. I cover the form with foil, but this is not necessary. Grease the bottom with vegetable oil in any case.
Brush the carcasses with the remaining sour cream and sprinkle with the cheese. Bake at 180 degrees for 20 minutes.