- salt and ground black pepper to taste
- 1 tablespoon Worcestershire sauce
- 2 tablespoons salted butter
- 1 large onion, thinly sliced
- 1 pound ground beef (80 percent lean)
- 3 rolls brioche, split and toasted
Place ground beef in a bowl and season with Worcestershire sauce, salt, and pepper. Mix thoroughly and shape into 3 balls. Set aside.
Melt butter in a large skillet. Add onion and cook until onions start to brown, 5 to 7 minutes. Remove from the skillet. Add 3 ground beef balls to the same skillet and flatten with a cast iron press or a heavy spatula. Evenly top each patty with onions and cook for 3 to 4 minutes more.
Carefully flip patties over so that the onions are now on the bottom, pressing once again with cast iron press or heavy spatula. Cook until burgers have reached the desired doneness, 3 to 4 minutes. Serve on brioche buns.