Stout Braised Short Ribs with Barley

Name: Stout Braised Short Ribs with Barley
Ingredients: 4 1/2 pounds bone-in short ribs, cut into 4-inch pieces; Kosher salt and freshly ground black pepper; 1/4 cup canola oil; 2 medium carrots, roughly chopped; 2 celery ribs, sliced; 2 medium onions, roughly chopped; 4 cloves garlic, sliced; 6 sprigs fresh thyme; 2 bay leaves; 2 sprigs fresh rosemary; Two 12-ounce bottles dark stout beer, such as Guinness; One 14.5-ounce can low-sodium beef broth; One 14.5-ounce can diced tomatoes; 1 cup pearl barley; 1 teaspoon dry mustard powder