2 ounces dried mushrooms, such as Polish borowik or porcini
2 cups warm water
6 ounces pearl barley, washed
10 cups Beef Stock
4 tablespoons unsalted butter
2 carrots, peeled and finely chopped
2 stalks celery, finely chopped
1/2 to 3/4 cup sour cream (optional)
3 tablespoons all-purpose flour (optional)
1/4 cup finely chopped fresh dill
1. Place the mushrooms in a small bowl. Add water and let soak overnight. Transfer mushrooms and soaking liquid to a small saucepan. Cook over medium heat until the mushrooms are tender, about 40 minutes. Drain mushrooms, reserving soaking liquid. Coarsely chop mushrooms; set aside.
2. Add barley to a small saucepan with 3 cups stock. Bring to a boil and let simmer until the barley is tender, about 45 minutes. Stir in butter; set aside.
3. In a medium saucepan, bring the remaining 7 cups stock to a boil with the carrots, celery, and reserved mushrooms and soaking liquid. Stir in the cooked barley mixture. Season with salt and pepper.
4. In a small bowl, stir together the sour cream and the flour. While stirring, slowly add 1 cup of the stock. Stir into soup with dill. Serve immediately.