Caramelized Onion Patty Melt

To make the caramelized onions, dice the onions finely. In a large pot or Dutch oven over low heat, melt the butter and oil.

Add the diced onions and salt to the pot. Cook over low heat, stirring occasionally, for about 1 hour and 20 minutes, or until the onions are deeply browned, sweet, and jammy.

While the onions cook, prepare the sauce. In a small bowl, combine the mayonnaise, ketchup, and pickle relish. Mix until smooth and set aside.

Form the ground beef into a ball. Place it between two sheets of parchment paper and press into a thin, wide patty that is slightly larger than your bread slices.

Season both sides of the beef patty generously with salt, black pepper, and dried rosemary.

Heat a skillet over high heat. Cook the patty for 2-3 minutes per side until a deep brown crust forms. Remove from the skillet and set aside.

In the same skillet, using the rendered beef fat, toast the bread slices until golden brown on one side.

Flip the bread slices. Spread sauce on the toasted side of one slice. Place the cooked patty on top, followed by the slice of American cheese.

Top the patty with a generous amount of the caramelized onions, then drizzle with more sauce.

Place the second slice of bread on top to complete the patty melt. Press down gently, slice in half, and serve immediately.