In a large bowl using your hands mix together the ground beef, onion soup mix, bread crumbs, and milk; form into eight patties.
In a medium size, bowl mixes together the soup and Au jus mix.
Roll the patties lightly in flour and brown them on both sides in a large skillet using the oil. Arrange the parries in a pyramid shape in the slow cooker and pour the soup mixture over the top.
Cook on low for 4-5 hours or until burger is done.
Serve hot with the gravy over the top of the patties and mashed potatoes.