01 - Heat a large skillet or griddle over medium-high heat. Add 1 tbsp butter and let it melt completely. Add the ground beef, spreading it into an even layer. Press down firmly with a spatula to achieve the signature smash burger crust. Cook undisturbed for 2-3 minutes until a deep brown sear forms, then break the meat apart into crumbles.
02 - Add the diced onion to the beef and cook for 3-4 minutes until softened and translucent. Stir in the minced garlic and cook for 1 additional minute until fragrant.
03 - Stir in the chopped pickles, ketchup, yellow mustard, Worcestershire sauce, brown sugar, smoked paprika, black pepper, and salt. Mix thoroughly and let the mixture simmer for 5-7 minutes, stirring occasionally, until thick and saucy.
04 - While the meat mixture simmers, butter the cut sides of each hamburger bun. Toast on a separate pan or griddle over medium heat until golden brown and crisp.
05 - Lay cheese slices directly over the hot meat mixture in the skillet. Allow them to melt slightly from the residual heat, then remove the skillet from heat.
06 - Spoon the cheesy beef mixture generously onto the bottom half of each toasted bun. Add sliced tomato and shredded lettuce if desired. Cap with the top bun and serve immediately while hot.