01 - Set your grill or grill pan to medium-high heat and allow it to reach full temperature before cooking.
02 - In a small mixing bowl, combine the ground coffee, brown sugar, smoked paprika, black pepper, kosher salt, garlic powder, onion powder, and cayenne pepper. Stir until evenly blended.
03 - Divide the ground beef into 4 equal portions and shape into patties. Generously coat both sides of each patty with the coffee rub, pressing gently so the seasoning adheres to the meat.
04 - In a small saucepan over medium heat, whisk together the ketchup, apple cider vinegar, brown sugar, Worcestershire sauce, smoked paprika, chipotle chili powder, garlic powder, onion powder, and salt. Bring to a simmer and cook for 5 to 7 minutes, stirring occasionally, until the sauce thickens slightly. Remove from heat and set aside.
05 - Place the seasoned patties on the hot grill. Cook for 4 to 5 minutes per side, or until the internal temperature reaches 160°F for medium doneness. If adding cheese, place a slice on each patty during the final minute of grilling and close the lid to melt.
06 - Place the hamburger buns cut-side down on the grill for 1 to 2 minutes until lightly toasted and golden.
07 - Spread a generous spoonful of smoky BBQ sauce on the bottom half of each bun. Layer with lettuce, the grilled burger patty, tomato slice, red onion, and additional sauce if desired. Cap with the top bun and serve immediately.