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 rye bread
- 3 tablespoons unsalted butter softened
- 4 Swiss cheese slices
- 4 cheddar cheese slices
Instructions
Make the Secret Sauce
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In a small bowl, combine the mayonnaise, ketchup, mustard, pickle juice, paprika, and garlic powder.
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Whisk until fully blended and set aside.
Cook the Onion and Beef
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Heat the olive oil in a skillet over medium-low heat. Add the sliced onions. Cook for 30-40 minutes, stirring occasionally, until the onions are deeply golden brown and caramelized. If the onions start to stick, add a splash of water.
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In a bowl, mix together the ground beef, salt, pepper, and Worcestershire sauce. Form into four thin, oval-shaped patties.
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Cook the patties in the same skillet over medium heat until browned, about 2-3 minutes per side. Remove and set aside.
Assemble and Cook the Sandwiches
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Spread one side of each bread slice with softened butter.
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Layer the bottom bread slices buttered-side down with Swiss cheese, beef patty, caramelized onions, secret sauce, cheddar cheese, and top bread slice buttered-side up.
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Cook in batches in the skillet over medium heat until both sides are golden brown and the cheese is fully melted, about 1-2 minutes per side.
Storage
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Store leftover secret sauce covered in the fridge for up to 5 days.
