you can use powder (just add hot water to a tsp or so of soup mix) or you can make your own from scratch. Or freeze the broth when you make pot roast or other meat.
I usually use powder in these recipes. If I don't have beef flavour I use chicken or vegetable.
You can likely subsitute chicken soup if you have any around. I freeze my leftover shabbso chicken soup so I often use that.
