Hi Elaine. I just use a kosher for Passover tin of gravy or packet of onion soup mix and use the liquid the beef cooked in. Or cook the beef with the soup as flavouring. Or cook the beef with e.g. kosher for Passover tomato and mushroom sauce.
Another nice gravy is half a bottle of ketchup with a small packet of prunes - much better than it sounds and tastes rich and better than the sum of its parts! Hope this helps.