Place the ground grass-fed beef in a bowl. Add kosher salt, black pepper, garlic powder, and Worcestershire sauce. Gently combine with your hands until just mixed; do not overwork. Divide into two equal portions and form into one thick (about 3/4 inch) patty if using whole pound for a single large burger or into two thinner patties if preferred. Make a shallow indent in the center of each patty with your thumb to prevent doming during cooking.

Bring to room temperature

Let the formed patty rest at room temperature 10–15 minutes while you prepare toppings and heat the pan. This ensures even cooking.

Toppings & Build

Prepare the toppings while patties rest: thinly slice the tomato and red onion. Rinse and dry the lettuce leaves. If using a bun, split and butter each cut face with the softened butter.

Mix mayonnaise and mustard together in a small bowl; set aside as the sauce.

Cook & Finish

Preheat pan

Place a heavy skillet or cast-iron pan over medium-high heat. Add olive oil and 1/2 tablespoon butter. Heat until butter foams and the pan is very hot but not smoking, about 2–3 minutes.

Cook the patty

Place the patty on the hot pan. For a 3/4-inch thick patty, cook 3–4 minutes on the first side undisturbed until a brown crust forms. Flip and cook another 3–4 minutes for medium (internal temp ~140–145°F / 60–63°C). Adjust time ±1–2 minutes for desired doneness. If cooking two thinner patties, reduce each side by about 1–1.5 minutes.

Add cheese

About 1 minute before the patty is done, reduce heat to medium-low, place the cheddar slices on top, and cover the pan briefly (or add a lid) to melt the cheese, about 30–60 seconds.

Toast the bun (optional)

While cheese melts, place the buttered bun faces, cut-side down, in another skillet or on the edge of the same pan and toast until golden, about 60–90 seconds. Remove and set aside.

Rest the patty

Transfer the cooked patty to a plate and let rest 2–3 minutes to redistribute juices.

Assemble

If using a bun: spread sauce on the bottom bun, place lettuce, add the cheesy patty, top with tomato slices, red onion, pickles, then spread mayonnaise/mustard on the top bun and close. For a bunless/low-carb option: use lettuce leaves to wrap the patty and layer toppings inside. Serve immediately.