
Mix the beef, breadcrumbs, egg, half the onion soup mix, Worcestershire, and pepper with your hands until just combined. Shape into 6 oval patties.
Scatter the mushrooms in the slow cooker and lay the patties on top (it's fine to overlap them a little).
Whisk the broth with the rest of the soup mix and pour it over the patties.
Cover and cook on LOW for 6 hours (or HIGH for 3) until the patties reach 160°F.
Gently lift out the patties. Whisk the cornstarch with 2 tablespoons cold water, stir it into the liquid, and cook on HIGH for 15 minutes until the gravy thickens.
Boil the egg noodles per the package, then serve the patties and mushroom gravy over the noodles.
Photo: DinnerDrop