01 -
In a large bowl, combine ground beef, Worcestershire sauce, garlic powder, onion powder, salt, and pepper. Mix gently to combine without overworking the meat. Divide the mixture into 4 equal portions and shape into thin, wide patties slightly larger than your bread slices. Heat olive oil in a skillet over medium heat and cook patties for 3-4 minutes per side or until fully cooked. Remove from the skillet and set aside.
02 -
In the same skillet, add 2 tablespoons of butter. Once melted, add the sliced onions and cook on medium-low heat for 10-12 minutes, stirring occasionally, until golden and caramelized.
03 -
Spread butter on one side of each bread slice. On the unbuttered side of four bread slices, layer 1 slice of cheddar cheese, a cooked beef patty, a scoop of caramelized onions, 1 slice of Swiss cheese, and another slice of cheddar cheese. Top with another slice of bread, buttered side facing out.
04 -
Wipe out the skillet and heat over medium heat. Place the assembled sandwiches in the skillet and cook for 3-4 minutes per side until the bread is golden brown and crispy, and the cheese is melted. Press lightly with a spatula for even toasting. Work in batches if needed, keeping finished sandwiches warm in a 200°F oven.
05 -
Slice each sandwich in half and serve immediately with your favorite dipping sauce or side of fries.