Barley Stuffed Peppers

Name: Barley-Stuffed Peppers
Ingredients: 3/4 cup uncooked barley, or 2 cups cooked barley or other grain; 2 tablespoons olive oil; 2 cups sliced cremini mushrooms; Kosher salt and freshly cracked black pepper; freshly cracked black pepper; 1/2 cup grated Parmesan cheese; 1 cup small-diced fresh mozzarella; 1/4 cup chopped fresh parsley; 1 yellow bell pepper, halved lengthwise and seeded; 1 red bell pepper, halved lengthwise and seeded; 1 cup bread crumbs