Place chopped onions and carrots in slow cooker with the roast on top of vegetables. Sprinkle with L&B Beef – Roast Seasoning. Cook on low for 8 hours or high for 4 hours.
Add the chopped potatoes into the slow cooker and stir with the other vegetables. Continue cooking for 2 hours on low or 1.5 hour on high, or until beef is fork tender and falls apart.
Season with salt and pepper, as desired. Garnish with parsley.