Clean the chanterelles and cut larger mushrooms. Peel and finely dice the onion and potatoes. Melt the fat in a saucepan, fry the mushrooms briefly, then remove them and keep warm. Sweat the onion and potato cubes lightly in the saucepan, deglaze with the stock and simmer covered for about 15 minutes over low heat. In the meantime, let the tofu rest in cold water for 5 minutes. Rinse the basil, shake dry and pluck the leaves off. Dice the tofu, stir into the soup and puree it smoothly in the mixer or with the hand blender. Bring to the boil again and season with soy sauce, pepper and sherry. add the chanterelles and heat briefly. Serve the soup sprinkled with basil.