Shape the Patties: Divide the ground beef into 4 equal portions for single burgers or 8 for double burgers. Gently shape each portion into a ball and flatten it into a round patty, about 4.7 inches (12 cm) wide and 0.4 inches (1 cm) thick, slightly larger than the bun.
Prepare the Ingredients: Get all the toppings and buns ready. Do not season the patties with salt until just before cooking to avoid toughening the meat.
Toast the Buns: Preheat the grill to high heat. Place the buns, cut side up, on a tray and toast for 3 to 5 minutes until lightly golden. If using a BBQ, toast them cut side down on the grill. Set the buns aside.
Season the Patties: Sprinkle one side of each patty with half the salt and pepper. Flip the patties and press a small dent in the center to prevent doming during cooking. Season this side with the remaining salt and pepper.
Cooking the Patties on the Stove: Heat a tablespoon of oil in a large cast-iron skillet over high heat until it’s very hot and starts smoking. Cook 2 to 4 patties at a time for 1 1/2 minutes, pressing down gently with a spatula. Flip the patties, immediately top each with a slice of cheese, and cook for another 1 1/2 minutes. Transfer the cooked patties to a tray and let them rest for 3 minutes.
Grilling the Patties on the BBQ: If your BBQ is well-seasoned, no extra oil is needed. Preheat it on high until it’s very hot and you see light smoke. Cook the patties as above, following the same timings and steps for flipping and adding cheese. You can also toast the buns on the BBQ, cut side down, for 2-3 minutes.
Assemble the Burgers: Spread your favorite sauce on the base of each bun. Layer with lettuce, tomato, a patty (double up if desired), gherkins, onion, and more sauce on the bun lid. Firmly place the top bun on the stack to finish assembling the burger.
Serve and Enjoy: Serve the burgers immediately with a side of French fries.