Combine the beef, bread crumbs, milk, eggs, and onion soup mix in a large bowl and mix thoroughly with your hands. Shape into eight 3 1/2 inch patties, each about 1/2 inch thick.
In a large skillet brown the patties until golden brown and firm up. Remove them onto a platter.
In the same skillet sauté the mushrooms and onions until the onions are translucent.
Place the chopped steak patties back into the skillet on top of the mushrooms and onions.
Place the brown gravy mix in a 4 cup or larger measure.
Add the amount of water called for on the envelopes and whisk until well blended.