Ingredients: 1½ pounds ground beef 2 teaspoons Worcestershire sauce 1 teaspoon kosher salt ½ teaspoon ground black pepper 12 slices sourdough bread ½ cup Secret Sauce 3 medium Vidalia onions, thinly sliced 6 slices Cheddar cheese 8 tablespoons unsalted butter Secret Sauce ¼ cup Dijon mustard ¼ cup mayonnaise 1 tablespoon barbecue sauce ½ teaspoon …

Ingredients: 1½ pounds ground beef 2 teaspoons Worcestershire sauce 1 teaspoon kosher salt ½ teaspoon ground black pepper 12 slices sourdough bread ½ cup Secret Sauce 3 medium Vidalia onions, thinly sliced 6 slices Cheddar cheese 8 tablespoons unsalted butter Secret Sauce ¼ cup Dijon mustard ¼ cup mayonnaise 1 tablespoon barbecue sauce ½ teaspoon …