Cut Roast In Half. In A Large Nonstick Skillet Coated With Nonstick Cooking Spray, Brown Meat On All Sides Over Medium-High Heat. Place Onion In A 5-Qt. Slow Cooker. Top With Meat. Combine The Broth, Gravy Mix, Garlic And Pepper; Pour Over Meat. Cover And Cook On Low For 6-7 Hours Or Until Meat And Onion Are Tender. Remove Meat To A Cutting Board. Let Stand For 10 Minutes. Thinly Slice Meat And Return To The Slow Cooker; Serve With Pan Juices And Onion.