Prepare the Secret Sauce

In a medium bowl, combine the mayonnaise, ketchup, Dijon mustard, pickle juice, paprika, and garlic powder. Mix until the sauce is smooth and well blended. Set aside until ready to assemble the sandwiches. This tangy, creamy sauce is what makes this Patty Melt with Secret Sauce truly special.

Prepare the Caramelized Onions

In a skillet over medium-low heat, heat the olive oil. Add the thinly sliced onions to the skillet. Cook, stirring occasionally, until the onions are softened and a deep golden brown, about 30 minutes or longer.

Tip: If the onions start to dry out or stick to the pan, add a splash of water and reduce the heat slightly. Once caramelized, remove the onions from the heat and set aside. Properly caramelized onions are crucial for an authentic patty melt experience.

Prepare the Patties

In a large bowl, combine the ground beef, salt, black pepper, and Worcestershire sauce. Mix gently until just combined; avoid overmixing to keep the patties tender. Divide the meat mixture into four equal portions. Shape each portion into a thin, oblong patty to match the shape of your bread slices.

Cook the Patties

In the same skillet used for the onions (wipe out any excess grease if necessary), heat over medium heat. Add the beef patties to the skillet. Cook for about 3–4 minutes on each side, or until browned and cooked to your desired level of doneness. Remove the patties from the skillet and set aside.

Assemble the Patty Melts

Butter one side of each slice of rye bread with the softened unsalted butter. For each sandwich, layer the ingredients as follows on the unbuttered side of the bread:

Place one slice of bread buttered side down on a plate or cutting board

Add one slice of Swiss cheese

Place a cooked beef patty on top of the cheese

Top with a generous portion of caramelized onions

Drizzle or spread some of the secret sauce over the onions

Add one slice of cheddar cheese

Top with another slice of bread, buttered side up

Cook the Sandwiches

Heat a skillet or griddle over medium heat. Place the assembled sandwiches onto the skillet. Cook for 1–2 minutes, or until the bottom slice of bread is golden brown and the cheese begins to melt. Carefully flip the sandwich using a spatula. Cook the other side for an additional 1–2 minutes, until golden brown and the cheese is fully melted. Remove from the skillet.

Serve

Slice each patty melt in half if desired. Serve immediately while hot. Enjoy your delicious Patty Melt with Secret Sauce!