Add the patties ingredients together to form 6 large patties. Brown in a large skillet….transfer to a 9×13 baking dish.
In the same skillet, using your drippings, sauté the mushrooms and onions until browned. Then sprinkle mushrooms and onion over patties.
In a saucepan combine gravy ingredients and bring to a simmer until bubbling and well combined. Pour over meat. Bake at 300° for 1 hour.
Remove from oven, take out patties and strain gravy to a separate saucepan.
Bring to a simmer….add in heavy cream.
Sprinkle in xanthum gum evenly over gravy whisking constantly until gravy thickens. Once your gravy thickens.
Pour over Salisbury steak.
Serve over faux mashed potatoes.