01 - Set a large skillet or griddle over medium-high heat. Add 1 tablespoon of unsalted butter and allow it to fully melt across the cooking surface.
02 - Add the ground beef to the skillet, spreading it into an even layer. Press down firmly with a spatula to achieve the signature smash burger crust. Let it cook undisturbed for 2 to 3 minutes until a deep golden-brown sear forms, then break the meat apart into crumbles.
03 - Stir in the finely diced onion and cook for 3 to 4 minutes until translucent and softened. Add the minced garlic and continue cooking for 1 additional minute until fragrant.
04 - Add the chopped dill pickles, ketchup, yellow mustard, Worcestershire sauce, brown sugar, smoked paprika, black pepper, and salt. Stir thoroughly to combine and let the mixture simmer for 5 to 7 minutes until thickened and glossy.
05 - While the beef simmers, butter the cut sides of each hamburger bun. Place them buttered-side down on a separate pan or griddle over medium heat and toast until golden brown, about 1 to 2 minutes.
06 - Lay the cheese slices directly over the hot beef mixture. Allow them to rest for 1 to 2 minutes until slightly melted, then remove the skillet from heat.
07 - Spoon the cheesy beef mixture generously onto the bottom half of each toasted bun. Add sliced tomato and shredded lettuce if desired, then cap with the top bun. Serve immediately while hot.