In a large skillet, cook and crumble beef over medium heat until no longer pink, 10-12 minutes; drain. Add to a 3-qt. slow cooker. In same skillet, melt butter over medium-high heat. Add barley; cook and stir until lightly browned, 3-5 minutes. Add to slow cooker. Stir in the next 10 ingredients. Sprinkle with bread crumbs and cheese.
Cover and cook on high until heated through and barley is tender, about 4 hours. Discard bay leaf before serving. Garnish with fresh parsley if desired.
