In 4-qt. saucepan or Dutch oven, saute mushrooms and onion in margarine. With slotted spoon, remove mushrooms and onion from pan. Stir flour into pan drippings; cook and stir over medium heat until flour is browned. Gradually add broth and water; add remaining ingredients except mushrooms and onion. Bring to a boil; reduce heat. Cover; simmer 45 minutes, stirring occasionally. Add mushrooms and onion; simmer 15 minutes or until barley is tender. Additional water may be added if soup becomes too thick upon standing. SIX 1 CUP SERVINGS NOTE: To substitute Quaker Scotch Brand Quick Pearled Barley, increase barley to 1/2 cup; proceed as recipe directs, adding mushrooms and onions along with remaining ingredients. Bring to a boil; reduce heat. Cover; simmer 10 to 12 minutes or until barley is tender, stirring occasionally. NUTRITIONAL ANALYSIS per serving: calories 212 carbohydrates 18 g protein 8 g fat 12 g calcium 24 mg sodium 780 mg cholesterol 0 mg * dietary fiber 2 g