Boil 400 ml water with soy cream. Stir in polenta and let it swell at low heat for about 10 minutes, stirring occasionally.
Meanwhile wash and halve the tomatoes. Clean the mushrooms, wash them if necessary and grate them dry. Heat the oil in a pan. Sauté the mushrooms in it for 1-2 minutes. Add the tomatoes and fry for 1-2 minutes. Salt, pepper and deglaze with vinegar.
Season the polenta with salt and fill into small bowls. Add the mushroom tomatoes. Sprinkle with linseed and cress as desired. Serve immediately.