In a bowl or resealable bag, combine the soy sauce, minced garlic, lemon juice, brown sugar, ginger, and toasted sesame seeds. Stir well to dissolve the sugar and create an evenly mixed marinade with distributed flavors. I like to use a resealable bag for this step because it minimizes cleanup and makes coating the steak easier in the next step.

Pat the porterhouse steak dry with paper towels, then season both sides generously with Morton kosher salt and black pepper. Place the steak in the bag with the marinade from Step 1 and massage it thoroughly to coat all surfaces, ensuring the marinade reaches into the crevices and around the meat. Refrigerate for 20 minutes to allow the flavors to penetrate the steak—I find 20 minutes is the sweet spot for flavor without over-salting the meat.

While the steak marinates, light your charcoal and let it burn for 10-15 minutes until the coals are glowing hot and covered with ash. Spread the hot coals into a flat, even pile across the bottom of your grill to create consistent, direct heat. This even distribution ensures your steak will cook uniformly without hot spots causing uneven browning.

Remove the steak from the marinade and pat it completely dry with paper towels—this is crucial for achieving a proper sear and crust. Place the steak directly over the hot coals and grill for 8-10 minutes per side, aiming for an internal temperature of 120°F for medium-rare (the steak will continue cooking slightly while resting). Resist the urge to move the steak frequently; let it develop a flavorful crust by staying in contact with the heat.

Transfer the grilled steak to a cutting board and let it rest for 10 minutes without cutting into it—this allows the juices to redistribute throughout the meat, keeping it tender and juicy when you slice it. After resting, slice against the grain and serve immediately while still warm.