Caramelize the Onions

1. Cook the Onions: Heat a skillet over medium heat and add a tablespoon of butter. Once melted, add the thinly sliced onions. Stir them occasionally, allowing them to cook down and turn golden brown, about 10 minutes. If they start to stick to the pan, you can add a splash of water to loosen them up. Once caramelized, set them aside.

Prepare the Patties

2. Make the Patties: In a bowl, combine the ground beef with Worcestershire sauce, garlic powder, salt, and pepper. Mix gently, being careful not to overwork the meat. Divide the mixture into 4 even portions and shape them into patties that are slightly larger than the slices of bread (the patties will shrink while cooking).
3. Cook the Patties: Heat a skillet or grill pan over medium-high heat. Add a bit of butter or oil to coat the pan. Cook the patties for about 4-5 minutes per side, or until they reach your desired doneness. For the perfect patty melt, aim for medium to medium-well so the cheese has time to melt perfectly when added.

Toast the Bread

4. Toast the Bread: While the patties cook, butter one side of each slice of bread. Once the patties are cooked, remove them from the skillet and set them aside. In the same skillet, add the slices of bread, butter side down. Toast the bread until golden brown and crispy, about 2-3 minutes per side. You may need to do this in batches if your pan isn’t large enough to hold all the bread at once.

Assemble the Patty Melt

5. Build the Sandwich: Once your bread is toasted, place a slice of Swiss cheese on the bottom slice of each piece of bread. Add the cooked beef patty on top, followed by a generous helping of caramelized onions. Top with another slice of Swiss cheese, then place the second piece of toast on top, butter side out.
6. Grill the Patty Melt: Carefully place the assembled sandwiches back into the skillet. Cook for about 3-4 minutes on each side, pressing down gently with a spatula to ensure even grilling. You want the cheese to melt and the bread to turn a golden, crispy brown. Keep an eye on the heat to prevent burning.

Serve

7. Cut and Serve: Once the patty melt is golden and the cheese is gooey, remove it from the pan. Let it cool for a minute, then slice in half diagonally (for that classic diner look) and serve immediately. You can pair it with crispy fries, a side salad, or even some pickle spears for the perfect meal.