Rinse barley under cold water.
In a pot, bring water and salt to a boil.
Add barley, reduce heat, cover, and simmer for 25-30 minutes.
In a pan, heat olive oil over medium heat.
Add onion and garlic, sauté until translucent.
Add carrot, celery, and mushrooms, cook until tender.
Stir in thyme and rosemary.
Combine cooked barley with vegetable mixture.
Season with salt and pepper to taste.