These slow cooker Salisbury steaks are juicy, fork-tender beef patties smothered in a savory mushroom and onion gravy. A classic comfort dinner that practically makes itself.
Place the sliced onions, mushrooms, and minced garlic into the bottom of the slow cooker.
In a large bowl, combine the ground beef, bread crumbs, milk, egg, Worcestershire sauce, salt, and pepper. Mix until just combined, then form the mixture into 8 equal-sized oval patties.
Heat a large skillet over medium-high heat and add the olive oil. Brown the patties on both sides, about 3 to 4 minutes per side. You're not cooking them through at this stage; you're just building a flavorful crust. Transfer the browned patties to the slow cooker, layering them on top of the onions and mushrooms.
In a separate bowl, whisk together the beef broth, cream of mushroom soup, and beefy onion soup mix until smooth and well combined. Pour this mixture evenly over the beef patties. Place the lid on the slow cooker and cook on the low setting for 4 to 5 hours, until the beef is cooked through and the gravy has thickened slightly.
Spoon the gravy generously over the patties before serving.
Notes
Don't skip the browning step. Taking a few minutes to sear the patties in a hot skillet before they go in the slow cooker adds a layer of flavor you won't get otherwise. The crust helps keep the patties intact too.
Don't overcrowd the skillet. Brown the patties in batches if needed so they sear rather than steam.
Use low and slow. Cooking on low for 4 to 5 hours keeps the patties juicy and tender. Cooking on high can work in a pinch but risks drying out the meat.
Whisk the gravy well before pouring. You want a smooth, lump-free sauce that distributes evenly over all the patties.
Taste and adjust at the end. Once everything is done, give the gravy a taste before serving. A splash of Worcestershire or a pinch of black pepper can go a long way if you want a little more depth.