Patty Melt with Secret Sauce

Enjoy restaurant-style comfort food at home with this easy Patty Melt recipe topped with melted cheese, sweet caramelized onions and a delicious Secret Sauce.

 Ingredients

 For the Secret Sauce

• 1/4 cup mayonnaise
• 2 tablespoons ketchup
• 1 tablespoon Dijon mustard
• 1 teaspoon pickle juice
• 1/4 teaspoon paprika
• 1/4 teaspoon garlic powder

 For the patty Melts

• 2 tablespoons olive oil
• 2 large onions, thinly sliced ​​
• 12 ounces 85/15 lean ground beef
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper
• 1 teaspoon Worcestershire sauce
• 8 Slices of rye bread
• 3 tablespoons softened, unsalted butter
• 4 slices of Swiss cheese
• 4 slices of cheddar cheese

Instructions

 Making the secret sauce

1. In a small bowl, combine the mayonnaise, ketchup, mustard, pickle juice, paprika and garlic powder.
2. Beat until completely combined and set aside.Preparing the onions and meat
3. Heat the olive oil in a frying pan over medium-low heat. Add the sliced ​​onions. Cook, stirring occasionally, until the onions are deep golden brown and caramelized, 30-40 minutes. If the onion starts to stick, add a splash of water.2. In a bowl, combine ground beef, salt, pepper and Worcestershire sauce. Form four thin, oval flat cakes.
4. Fry burgers in the same pan over medium heat until golden brown, about 2-3 minutes per side.Remove and reserve.

 Assemble and bake the sandwiches.

1. Brush one side of each slice of bread with softened butter.
2. Top and bottom slices of bread butter side down with Swiss cheese, beef patties, caramelized onions, secret sauce, cheddar cheese and top slice of bread butter side up.3. Cook in batches over medium heat until both sides are golden brown and  cheese is completely melted, about 1-2 minutes per side.

 Storage

1. Store the remaining Secret Sauce covered in the refrigerator for up to 5 days.