Put the oil and onion in a soup kettle, set over low heat, and cook until the onions are softened, about 5 minutes. Raise heat to medium, stir in the garlic and carrots, and stir-cook for one minute. Add the celery and stir-cok for a minute. Add the barley, broth, bay leaf, and allspice. Bring to the boil, skimming the top of the soup as necessary. Simmer, covered, for about one hour, or until the barley is tender. (The soup may be prepared in advance to this point.) Stir the ham into the piping hot soup and let simmer while you prepare the mushrooms. Heat the butter in a small skillet, add the mushrooms and lemon juice, and stir-cook for 2 to 3 minutes. Stir in the parsley. Add the mushroom mixture to the soup and simmer for 5 minutes longer. Discard the bay leaf. Season the soup with salt and freshlyground pepper to taste. Ladle into warmed bowls and serve immediately. Makes 5 servings. [WASHINGTON POST Jan 11, 1989]