5-Star Salisbury Steak

Ingredients

• 1 pound 90% lean ground beef
• 1/2 yellow onion, finely diced
• 2 cloves garlic, minced
• 1/3 cup panko breadcrumbs
• 1 large egg
• 1 1/2 teaspoons Worcestershire sauce
• 2 teaspoons mayonnaise
• 1 teaspoon sea salt
• 1/2 teaspoon black pepper
• 1 1/2 teaspoons Italian seasoning
• 1 tablespoon ketchup
• 1 1/2 teaspoons milk
• 2 teaspoons Dijon mustard
• 1 tablespoon olive oil
• 1 tablespoon unsalted butter
• 8 ounces brown mushrooms, sliced
• 1/4 teaspoon sea salt, plus more, to taste
• 1/8 teaspoon ground black pepper, plus more, to taste
• 2 tablespoons all-purpose flour
• 1 1/2 cups beef broth
• 1/2 cup water
• 1/2 teaspoon Worcestershire sauce
• 1/2 teaspoon Dijon mustard
• 2 teaspoons ketchup