Peel, wash and cut onions into cubes or thin half rings.
Wash and clean the mushrooms. Cut the mushrooms into slices or cubes.
Preheat a frying pan, pour in vegetable oil. Put prepared onion into hot oil. Simmer over medium heat, stirring occasionally, for 2-4 minutes, until the onion is golden.
Place the mushrooms in the pan. Simmer everything together, stirring occasionally, for 5-7 minutes. Season with salt, pepper, add your favorite spices. Mix.
Pour tomato juice over the mushrooms. Simmer mushrooms in tomato sauce over low heat for 5 minutes.
Mushrooms in tomato sauce are ready. Serve with your favorite side dish.