In large saucepan, heat oil over medium heat. Add mushrooms and leeks; salt and pepper to taste. Sauté until softened (about 5 minutes).
Stir in barley, chicken broth and rosemary; bring to a boil. Reduce heat, cover and simmer 45 minutes or until barley is tender and liquid is absorbed.
Remove from heat; stir in cheese. Salt and pepper to taste.