Puree is any aggregate state of potatoes since childhood. Nowadays we use masher to make puree, but at the beginning of the 20th century we used metal devices similar to a garlic press, only 2-3 times larger. Oyster mushrooms and champignons are mushrooms that can be found in any store at any time of the year. Therefore, if you want potatoes with mushrooms in winter, then mashed potatoes with champignons and oyster mushrooms are what you need!