Place the potatoes, onion, carrots and mushrooms in slow cooker. Add bay leaf and sprinkle with thyme. Cut steak into chunks, then place the meat on top of vegetables.
In a mixing bowl, combine the onion soup mix, cream of mushroom soup, water, worcestershire sauce and soy sauce; pour over beef.
Cover slow cooker, and cook on Low for 6 to 8 hours or High 3 to 4 hours.