Preparation

• In a large bowl, mix together the ground beef, egg, breadcrumbs, onion soup mix, milk, and Worcestershire sauce until well combined.
• Divide the mixture into 8 even portions and form them into patties.
• Place the flour on a small plate and dip both sides of the patties into the flour, tap off any excess.
• In a large skillet over medium-high heat, add the oil. Once hot, sear the patties in batches until golden brown, do not cook the patties all the way through.
• Spray a 6-quart or similar-sized slow cooker with cooking spray. Layer the patties into the slow cooker.
• In a large bowl, whisk together the beef broth, au jus gravy mix, garlic, Worcestershire sauce, and dijon mustard. Pour this mixture over the patties.
• Slow cook on low for 4-5 hours or high 3-4 hours until the patties reach an internal temperature of at least 165°F.
• Place the patties onto a plate.
• Place the gravy into a large skillet and bring to a simmer.
• In a small bowl, whisk together the water and cornstarch. Slowly stream in the cornstarch slurry while constantly whisking into the simmering gravy. Simmer until thickened, 1-2 minutes.
• Serve the patties immediately or place them back into the slow cooker and pour the thickened gravy on top.
• Keep on the warm setting. Serve with mashed potatoes, egg noodles or rice.