Jucy Lucy Burger

1. Prepare the caramelized onions: Finely dice a yellow onion. Melt butter in a large skillet over medium heat. Add the diced onions and a pinch of salt. Sauté until the onions are soft and translucent. Pour in some water and continue to cook, stirring occasionally, until the onions are deeply browned and caramelized. Set aside.
2. Prepare the patties: Divide the ground beef into four equal balls. Place two balls on a sheet of parchment paper, leaving space between them. Cover with another sheet of parchment paper and press down firmly to create two very thin, wide patties. Repeat with the remaining two balls of beef.
3. Stuff the burger: Take one thin patty and place a slice of American cheese in the center (you may need to fold it). Place a second thin patty on top. Carefully pinch and seal the edges all the way around to completely enclose the cheese.
4. Cook the burger: Heat cooking oil on a griddle or cast-iron skillet over medium-high heat. Season the outside of the stuffed patty generously with salt. Place the patty on the hot griddle and cook for 4-5 minutes per side, or until a deep brown crust has formed and the burger is cooked to your liking.
5. Toast the buns: While the burger is cooking, place the burger buns cut-side down on the griddle to toast until golden brown.
6. Assemble the burger: Spread special sauce on the cut sides of both the top and bottom toasted buns. Place the cooked Jucy Lucy patty on the bottom bun. Top with a generous amount of caramelized onions and sliced pickles. Place the top bun on and serve immediately.