Heat the oil in a frying pan and sauté the mushrooms directly from frozen.
Once the mushrooms are golden, sprinkle them with flour. Mix well and cook for 1-2 minutes. Remove the pan from heat.
Slice the onion and grate the carrots.
Heat the remaining oil in another frying pan. Sauté the onion and carrots until softened. Lightly season with salt and pepper to taste. Remove the pan from heat.
Cut the potatoes into cubes about 1–1.5 cm on each side.
Bring about 3 liters of water to a boil in a large pot. Add the potatoes and bring back to a boil.
Reduce the heat, add salt, mushrooms, and bay leaves, and simmer.
Add the sautéed vegetables to the pot. Cook everything together for another 10–15 minutes.
Serve hot in bowls. Add a tablespoon of sour cream to each serving and sprinkle with dill or chives.