Coat a large, nonstick frying pan with olive oil (thin layer, just to coat). Add one more teaspoon of olive oil to the bottom of the frying pan and heat over medium flame.

Add diced onion, mushrooms, and garlic; sauté until mushrooms are tender.

Add barley and next three ingredients. Bring to a boil. Cover, reduce heat, and simmer for about 1/2 hour, until barley is tender and most of the water is absorbed.

Remove from heat and let stand five minutes. Sprinkle with cheese, if desired. Serve warm.