01 - In a small mixing bowl, combine the finely ground coffee, brown sugar, smoked paprika, chili powder, garlic powder, onion powder, and cayenne pepper. Stir until all spices are evenly distributed.
02 - In a small saucepan over medium-low heat, combine the ketchup, apple cider vinegar, brown sugar, Worcestershire sauce, liquid smoke, smoked paprika, garlic powder, black pepper, and salt. Simmer for 5 to 7 minutes, stirring occasionally, until the sauce thickens. Remove from heat and set aside.
03 - Divide the ground beef into 4 equal portions, shaping each into a patty slightly wider than the burger buns to account for shrinkage. Season both sides of each patty with kosher salt, black pepper, and a generous coating of the coffee rub, pressing the seasoning gently into the meat to adhere.
04 - Preheat your grill or grill pan to medium-high heat, approximately 400°F. Ensure the grates are clean and lightly oiled to prevent sticking.
05 - Place the seasoned patties on the hot grill. Cook for 4 minutes without moving, then flip. If using cheese, place a slice on each patty immediately after flipping. Grill for another 3 to 4 minutes for medium doneness, or adjust time to reach your preferred temperature.
06 - During the last minute of cooking, place the burger buns cut-side down on the grill to toast until lightly golden, about 1 minute.
07 - Spread a generous layer of smoky BBQ sauce on the bottom half of each toasted bun. Layer with lettuce, the hot coffee-rubbed patty, tomato slices, red onion rings, pickles, and additional sauce if desired. Cap with the top bun and serve immediately while hot.