1 tablespoon olive oil
1 cup chopped onion
12 ounces coarsely chopped button and/or crimini mushrooms
1 large portobello mushroom, gills removed, cap and stem chopped
3 tablespoons chopped fresh parsley
1 tablespoon chopped fresh thyme
1 tablespoon minced garlic
1 cup pearl barley
5 cups (or more) canned low-salt chicken broth or vegetable broth
2 tablespoons tomato paste
1/4 cup grated Parmesan cheese
Heat oil in heavy large saucepan over medium heat. Add onion; sauté 4 minutes. Add all mushrooms; sauté until golden brown, adding 1 to 3 tablespoons water if mixture is dry, about 15 minutes. Stir in herbs and garlic. Add barley and stir 1 minute. Add 4 cups broth and bring to boil. Reduce heat to medium; cover and cook until liquid is almost absorbed and barley is almost tender, about 30 minutes.
Stir 1 cup broth and tomato paste into barley. Cook uncovered until barley is tender and mixture is creamy, stirring occasionally and adding more broth if necessary, about 10 minutes. Stir in cheese. Season with salt and pepper.