The night before, soak the dried mushrooms in a quart of water.
Chop the garlic, shallots and onions finely and sauté until translucent in butter in a sauté pan. Set aside.
Remove the mushrooms from the water where they had been soaking overnight and mince them finely as well. Sauté with butter slowly for 15 minutes. Do not discard the water.
While your mushrooms are sautéing slowly, dice the potatoes into small cubes and set aside.
After your onions, garlic and shallots have been sautéed and your mushrooms sautéed as well, take the water in which the mushrooms have been soaking and pour it carefully into a large pot. Carefully because the silt and sand will settle at the bottom of the pot and you want to avoid pouring it into your soup. So, pour all but the remaining half an inch. Pour slowly to monitor the silt at the bottom.
Add to your liquid 4 quarts of chicken stock or vegetable stock.
Add the onion medley, the mushroom, the potatoes and the barley.
Cook over a slow simmer for an hour before tasting. Then add salt, pepper and sugar according to taste. Once you achieve your flavors, let the soup simmer gently for another hour and a half.
Serve with a dollop of sour cream in the centre.