Make It:

• Thinly slice the onions. Heat a large skillet over medium-low heat and add the butter. Once melted, add in the onions with JB Worcestershire sauce. Stir to combine everything. Cook, stirring often, for 4 to 5 minutes, until the onions caramelize.
• Heat a large cast iron skillet or your grill griddle over medium-high heat.
• Place half of the butter on the skillet. Place the burger patty onto the skillet and smash it down with a burger press or spatula once or twice.
• Cook the burgers patty for 2 to 3 minutes, season with the burger patty with JB Worcestershire sauce and then flip, season with the burger patty with JB Worcestershire sauce on the other side and cook for 2 minutes more. Add the cheese and let it melt for just 60 seconds or so.
• Meanwhile, cut the burger bun into two, spread some butter onto the bun and heat it on the hot iron skillet until golden brown.
• Remove the burgers patty and bun from the heat. Spread the sauce onto the buns and top with a piece of lettuce. Add the burger patty on, along with the caramelized onions. Serve immediately!