Line the bottom of your crockpot with the sliced mushrooms and onion.
In a large mixing bowl, mix together the ground beef, breadcrumbs, egg, and garlic powder. Form the mixture into small round fat patties.
Season the patties with steak seasoning or salt and pepper and then heat them on medium heat for 3 minutes on each side. This will give them a nice sear and help hold together as they cook in the crockpot.
Add the patties to the top of the mushroom and onions in the crokpot.
Sprinkle the brown gravy mix evenly on the top of the patties.
Pour the can of mushroom soup on top of the patties followed by the beef broth; cover crockpot.
Cook on high for 6 hours; stirring twice throughout cooking time, if possible.