Make dinner easy with this Salisbury Steak Casserole! All the classic flavors your family loves like juicy ground beef, rich gravy, and fluffy mashed potatoes in one dish.
Preheat oven to 350F. Spray a 9×13 pan with nonstick spray.
In a large skillet cook the ground beef and ⅓ can of french onion soup until the meat is no longer pink. Remove to a bowl and drain excess fat.
To the skillet add the butter. Saute the mushrooms and onions in the butter until the mushrooms are brown and the onions are tender.
Spread the ground beef in the prepared 9×13 pan.
In a medium bowl, combine the remaining ⅔ french onion soup, onion soup mix, condensed mushroom soup, ketchup, water, Worcestershire sauce, flour, salt, pepper, and mustard. Stir to mix.
Pour soup mixture over the ground beef in the 9×13 and spread into an even layer.
Top the soup mixture with the mushrooms and onions.
Drain and rinse the canned green beans.
Spread them over the mushrooms and onions.
Top with prepared mashed potatoes and spread into an even layer.
Bake at 350F for 25-30 minutes or until the casserole is bubbly and the internal temperature has reached 165F.
Remove and let set for 3-5 minutes (it will be runny a little)
Serve warm and enjoy.
Notes
Get a golden top - Broil for the last few minutes if you want extra browning, but watch carefully.
Easy cleanup - Spray casserole dish with cooking oil before assembling.
Adjust consistency - Add a tablespoon or two of beef broth to add moisture to meat mixture.
Let it rest - Allow casserole to sit a few minutes after baking so everything thickens and becomes easier to serve.