Kosher salt and freshly ground black pepper, to taste
Preparation:
In a large bowl, combine ground beef, breadcrumbs, egg, Dijon mustard, ketchup, and 1 tablespoon Worcestershire sauce. Season generously with salt and pepper, mix until well combined, and roll the mixture into 1 1/2-inch meatballs.
Heat olive oil in a large skillet over medium-high heat. Working in batches, brown the meatballs on all sides until golden. Transfer to a plate and set aside.
Reduce heat to medium. Add sliced onions to the skillet and cook until softened and lightly caramelized, about 5-10 minutes.
Add butter to the skillet. Once melted, stir in minced garlic and cook until fragrant, about 1 minute.
Whisk in flour and cook for another minute to create a roux. Slowly pour in beef stock, stirring constantly, until the sauce becomes bubbly and thickened.
Stir in the remaining Worcestershire sauce and season with additional salt and pepper to taste.
Return the meatballs to the skillet and simmer in the sauce until cooked through, about 3-4 minutes.
Serve these Salisbury Steak Meatballs over egg noodles or mashed potatoes for the ultimate comfort food experience.