In a large bowl mix 1/3 can of cream of mushroom soup, ground beef, bread crumbs, egg and pepper. You can mix with a spoon or I prefer my hands. Shape into 6 Salisbury steak patty shapes.
Heat a skillet to medium high heat and add steaks, browning them on both sides. Note: You are not completely cooking the ground beef, but only browning on both sides. Add steaks into 9x9 baking dish.
In a medium-sized bowl whisk together remaining cream of mushroom soup and flour, mixing until the soup is no longer clumpy. Add ketchup, broth, Worcestershire sauce and mustard power, and continue mixing. Pour this mixture on top of the steak patties.
Cover with aluminum foil and bake for 1 hour, or until the internal temperature reads 160 °F. Remove from oven and serve.
Recipe Created by Pamela Reed for brooklynfarmgirl.com