This "knife and fork" style beer-braised burger does most of its cooking in a delicious sudsy bath of brew, which not only builds in a great depth of flavor, it also helps to create a killer pan sauce that you can pour over your finished masterpiece.
While the onions are cooking, season the ground beef with salt and pepper and form it into four patties. Push the softened onions to the outer edge of the skillet and add the burgers to the pan. Cook the burgers until browned on one side, 2 to 3 minutes, and then flip them over. Add the beer, Worcestershire sauce and Dijon mustard to the pan and swirl it gently to combine all of the ingredients. Continue cooking the burgers to your desired doneness, about 4 minutes for medium. Once the burgers are finished, remove them to a plate and continue reducing the liquid in the pan until it reaches a glossy, gravy-like consistency. Season with salt and pepper.