Instructions:
Prepare Salisbury Steak Mixture: Combine ground beef, breadcrumbs, milk, onion soup mix, and thyme in a large bowl. Mix gently until well combined.
Shape and Brown Patties: Form the beef mixture into oval patties. Heat olive oil in a skillet over medium-high heat. Brown the patties on both sides and transfer to the slow cooker.
Sauté Onions: In the same skillet, sauté sliced onions until golden brown. Add the onions to the slow cooker.
Create Gravy Base: Sprinkle flour into the skillet drippings and cook until golden brown.
Slow Cooker Assembly: Add the roux, cream of chicken soup, water, and au jus mix to the slow cooker. Stir until combined.
Cook to Perfection: Nestle the browned patties into the gravy. Cook on low for 4-6 hours.
Serve: Serve the Salisbury steak with mashed potatoes, rice, or noodles, topped with the gravy.
