Ingredients:
2 pounds ground beef
2 tablespoons Worcestershire sauce
½ teaspoon garlic powder
½ cup butter (divided)
1 extra-large sweet onion, peeled and thinly sliced
12 slices thick-cut sandwich bread (Texas toast)
6 slices American cheese
6 slices Swiss cheese
2 tablespoons yellow mustard
Salt and pepper
Instructions:
Caramelize Onions:
In a skillet over medium heat, melt 4 tablespoons of butter and sauté onion slices until caramelized. Season with salt and pepper.
Prepare Beef Patties:
In a bowl, mix ground beef with Worcestershire sauce, garlic powder, salt, and pepper. Divide into six portions and shape into flat ovals.
Assemble Patty Melts:
Spread mustard on 6 slices of bread. Cook beef patties on a griddle or skillet, flipping after 3 minutes.
Top each patty with caramelized onions, American cheese, and Swiss cheese. Cook for six minutes in total.
Final Assembly:
Place each patty on mustard-spread bread slices. Melt 2 tablespoons of butter on the griddle.
Place patty melts on the griddle, cover with remaining bread slices, and toast until golden brown.
Add remaining butter, flip, and toast the other side until golden.
Serve:
Transfer patty melts to a cutting board with cheese on top of the patties. Cut in half and serve hot.