01 -
Spray 6-quart oval slow cooker with cooking spray. Add sliced mushrooms and onions to bottom.
02 -
Mix ground beef, steak seasoning, 1 tablespoon Worcestershire sauce, dried onion flakes, parsley, breadcrumbs, and egg. Form into 4-6 oval patties.
03 -
Place patties in slow cooker, spreading evenly without stacking.
04 -
Whisk beef broth, 2 tablespoons Worcestershire sauce, 2 tablespoons cornstarch, and black pepper until smooth. Pour over patties.
05 -
Cover and cook on high for 4 hours.
06 -
Remove steaks from slow cooker. Mix 1 tablespoon cornstarch with 2 tablespoons water, then stir into gravy until thickened.
07 -
Place steaks on egg noodles or mashed potatoes and top with mushroom and onion gravy.