Mix spices together (excluding bay leaf) and set aside.
Place carrots in the bottom of a slow cooker that has been sprayed with non-stick spray (or use a disposable slow cooker liner). Cut potatoes into 1 inch cubes and place on top of carrots. Cut onion into large chunks and add to the slow cooker. Top with bay leaves.
Generously rub roast with spice mixture on both sides. Place on top of vegetables and cook for 6-8 hours on low.
Remove from slow cooker and discard bay leaves.
Recipe by southern kissed at http://www.southernkissed.com/slow-cooker-seasoned-roast/