Combine together the Italian and steak seasoning. Add them to the rump or chuck roast.
Prepare the slow cooker. Fill it with the carrots, roast, celery, beef broth, onions, and potatoes. If you set it on high you should cook for 6 hours, if you set it on low you should cook for 9 hours.
Remove the liquid part from the cooker in a pan. Mix it with the onion powder, garlic powder, salt, and pepper. Wait for the mixture to boil.
In a bowl combine the cold water and cornstarch. Add the mixture to the pan. Lower the heat and cook it for 3 to 5 minutes.
Serve the meat with the gravy on top and the vegetables on the side.