Add the ground beef, breadcrumbs, eggs, Worcestershire sauce, ketchup, dijon mustard, garlic powder, onion powder, salt, and pepper to a large bowl. Gently mix until just combined, then form the mixture into 6 evenly sized patties.
1 1/2 pounds ground beef, 1/3 cup breadcrumbs, 1 teaspoon Worcestershire sauce, 2 teaspoons ketchup, 1 teaspoon dijon mustard, 1/2 teaspoon garlic powder, 1/2 teaspoon onion powder, 1/4 teaspoon salt, 1/4 teaspoon black pepper, 2 large eggs
Heat 1 tablespoon of the olive oil in a large skillet over medium-high heat. Working in batches, if necessary, brown the patties for 2–3 minutes per side. Add the remaining olive oil as needed. Transfer the browned patties to the slow cooker.
1 Tablespoons olive oil, 1 Tablespoons olive oil
In a medium bowl, whisk together the beef stock, gravy mix, ketchup, Worcestershire sauce, and soy sauce until well combined. Pour the gravy mixture over the patties.
2 cups beef stock, 2 packets gravy mix, 1 teaspoon ketchup, 1 teaspoon Worcestershire sauce, 1 teaspoon soy sauce
Cover and cook on high for 2 hours, or until the Salisbury steaks are cooked through and reach an internal temperature of 160° F.
Serve the Salisbury steaks and gravy over mashed potatoes or egg noodles.