Ingredients
5 to 6 ounces (about 4 to 6) dried mushrooms such as Polish borowik or cepes
12 large dried shiitake mushrooms
3 quarts Homemade Beef Stock
5 medium ribs of celery, chopped
2 large onions, chopped
5 carrots, chopped
1 pound white button mushrooms, sliced
1 cup orzo
2 tablespoons unsalted butter
2 tablespoons flour
1 cup sour cream
2 tablespoons parsley, finely chopped
2 tablespoons dill, finely chopped
Salt and freshly ground black pepper
Preparation
Rinse dried mushrooms. Place mushrooms in 2 cups of cold water, and soak for at least 4 hours or overnight.
In a large pot, bring stock to a simmer. Add celery, onions, and carrots. Strain dried mushrooms, reserving the soaking liquid. Add strained soaking liquid to soup. Chop hydrated mushrooms into 1/4-inch pieces slightly larger than diced vegetables, and add to soup. Add sliced white button mushrooms.
Cover, and cook soup until vegetables are tender, about an hour. Bring soup to a boil. Stirring constantly, add orzo. Reduce the heat to a gentle boil, and, stirring occasionally to prevent pasta from sticking, cook until orzo is cooked through, another 6 to 8 minutes.
Meanwhile, make a roux: Melt butter in a small saucepan over medium heat. Add flour, and cook, stirring constantly until smooth, 3 to 5 minutes. Remove 1 cup broth from soup,and add roux, whisking constantly until slightly thickened and free of lumps. Stir thickened liquid into soup. Add chopped parsley and dill.
Finish soup with sour cream: Add 1/4 cup thickened soup to sour cream. Whisk until smooth. Add sour cream to soup, whisking constantly until it is well incorporated, about 3 minutes. Season to taste with salt and pepper.
