Place eggplant in a large shallow baking dish. Mix together the soy sauce, sherry, sesame oil, and garlic in a small bowl. Pour the marinade over the eggplant and let marinate at room temperature for 1 hour. Preheat grill. Season the eggplant with salt and pepper to taste and grill on each side for 3 minutes, basting occasionally with the remaining marinade. Serve topped with the toasted sesame seeds.