Divide the ground beef into four equal portions. Gently form each portion into a patty, about 1 cm thick, without overworking the meat. Make a shallow indentation in the center of each patty with your thumb to prevent it from bulging while cooking.
Generously season both sides of the patties with salt and black pepper just before you are ready to cook.
Heat a grill or a large cast-iron skillet over medium-high heat. If using a skillet, add a small amount of oil.
Place the patties on the hot surface and cook for 3-5 minutes per side, depending on your preferred doneness. For a medium-rare burger, cook for about 3 minutes per side. Flip only once.
In the last minute of cooking, place a slice of cheese on each patty to melt.
While the patties are cooking, lightly butter the inside of the hamburger buns. Place them cut-side down on the grill or in the skillet for about 30 seconds to a minute, until lightly golden and toasted.
Place the cooked patty with melted cheese on the bottom bun. Top with fresh lettuce, tomato slices, onion, and pickles.
Add your favorite condiments to the top bun and place it on top of the burger.
Serve immediately and enjoy your classic American hamburger!