Lightly shape the 1/2 lb ground beef into a single patty about 3/4 to 1 inch thick and slightly wider than the bun. Do not overwork the meat — press gently to avoid compacting. Create a shallow dimple in the center with your thumb to prevent puffing during cooking.

Season

Season both sides of the patty with the kosher salt and freshly ground black pepper just before cooking.

Preheat Grill or Pan

Preheat a grill to high (450–500°F / 232–260°C) or heat a heavy skillet/griddle over medium-high heat. If using a skillet, add 1 tsp vegetable oil and heat until shimmering.

Cook

Place the patty on the hot grill or skillet. For a flame-broiled flavor on stovetop, let the pan get very hot and resist pressing the patty. Cook for 4–5 minutes on the first side without moving to develop a brown crust.

Flip and Finish

Flip the patty and cook for another 3–5 minutes for medium (internal temperature ~160°F / 71°C for well-done per USDA guidelines; cook to desired doneness). If using cheese, place the slice on the patty during the last minute and cover the grill or pan to melt.

Rest

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

Bun & Toppings

Toast the Bun: While the patty rests, spread 1 tsp softened butter or a thin smear of mayonnaise on the cut faces of the brioche bun. Place cut-side down on the hot grill or skillet for 30–60 seconds until golden and slightly crisp. Remove to a plate.

Prep Vegetables: Rinse and pat dry the lettuce leaf. Slice the tomato into 2 even slices (about 1/4 inch thick). If using onion, slice into rings and separate. Prepare pickles if desired.

Assemble: On the bottom half of the toasted brioche bun place the lettuce leaf, then the tomato slices. Add any pickles or onion rings you prefer. Place the rested burger patty (with melted cheese if used) on top of the tomato. Spread ketchup, mustard, and/or mayonnaise on the top bun and close the sandwich.

Serving

Serve immediately while hot with your choice of sides (fries, chips, or a side salad). If desired, secure the burger with a toothpick and slice in half for easier eating.