Cook barley in a medium pot of lightly salted water for 35 minutes or until tender. Drain.
Meanwhile, in a saucepan, heat oil over medium heat. Add onion and sauté until translucent. Add mushrooms and cook until browned, about 4-6 minutes.
Stir in garlic and cook for 30 seconds then add tomatoes, broth, Italian seasoning, and salt. Bring to a simmer and cook for 10 minutes. Add chard and cook until wilted.
Stir in cooked barley and butter. Top with gruyere cheese and cover. Continue cooking on low until cheese has melted.
Garnish with grated parmesan and serve.
