Heat the oil in a pan. Add the leek and garlic and sauté for approx. 5 mins. Add the mushrooms and cook for another 5 mins. approx. Add the potatoes, thyme, wine and stock, bring to the boil then reduce the heat, cover and simmer for approx. 20 mins. Remove the thyme and purée the soup. Stir in the cream and season.
Pearl barley topping
Cook the pearl barley in salted water for approx. 25 mins. until soft, drain. Heat the oil in a frying pan. Sauté the remaining mushrooms for approx. 5 mins., add the barley, sauté for approx. 3 more mins. approx., and season. Place the barley topping onto the soup and garnish with chives.