Step 1: Caramelize the Onions

1. Heat a skillet over medium heat. Add the butter and olive oil.
2. Once the butter melts, add the sliced onions. Sprinkle with salt and sugar (if using).
3. Cook, stirring occasionally, for 15–20 minutes until the onions are soft, golden, and caramelized. Reduce the heat to low if they begin to brown too quickly. Remove from the skillet and set aside.

Step 2: Prepare the Beef Patties

1. In a mixing bowl, combine the ground beef, Worcestershire sauce, garlic powder, onion powder, salt, and black pepper. Mix gently to avoid overworking the meat.
2. Divide the mixture into 4 equal portions and shape into rectangular or round patties slightly larger than your bread slices.

Step 3: Cook the Patties

1. Heat the skillet over medium-high heat. If needed, add a small amount of oil.
2. Cook the patties for 3–4 minutes on each side until browned and cooked to your desired doneness (medium is recommended). Remove from the skillet and set aside.

Step 4: Assemble the Patty Melts

1. Butter one side of each slice of bread.
2. Place a slice of bread, buttered side down, on a clean surface. Layer with one slice of cheese, a cooked patty, caramelized onions, another slice of cheese, and top with another slice of bread, buttered side up. Repeat for all sandwiches.

Step 5: Cook the Patty Melts

1. Heat a large skillet or griddle over medium heat.
2. Place the sandwiches in the skillet and cook for 3–4 minutes on each side, pressing gently with a spatula, until the bread is golden and the cheese is melted. Adjust the heat to prevent burning.

Step 6: Serve

1. Slice the patty melts diagonally and serve immediately.
2. Pair with classic sides like fries, onion rings, or a crisp salad.