Clean mushrooms and onions, cut. Tomatoes cut into slices. In a large skillet, heat the olive oil, perezharte onions, then add the mushrooms and tomatoes. Reduce heat and simmer for 20 minutes under the lid, do not forget to stir. At the end of cooking salt and pepper, add the basil and mix. This stew can be served with rice or pasta, sprinkle with grated cheese hot dish.