Chop onion and garlic finely, fry in vegetable oil until soft.
Cut the mushrooms into slices and add to the onion, cook over medium heat for 10 minutes.
Then add finely chopped tomatoes and cook for another 5 minutes.
Then add the chopped liver and simmer under the lid for 15 minutes. Season and salt to taste.
Add sour cream, mix well and keep on fire for a few more minutes.
Braised liver in sour cream with mushrooms is ready, serve hot.