How to Make It
In a large resealable plastic bag, combine all of the ingredients except the ham steak and sesame seeds and shake to mix. Add the ham steak and seal the bag, pressing out the air. Set the bag in a large baking dish and refrigerate overnight.
Light a gas grill. Remove the ham from the marinade and let stand at room temperature for 30 minutes.
Pat the ham dry with paper towels. Grill over high heat, turning once, until lightly charred, about 3 minutes per side. Flip the steak again and grill over low heat, turning occasionally, until an instant-read thermometer inserted in the thickest part registers 140°, 20 to 25 minutes.
Transfer the ham steak to a carving board and let rest for 10 minutes. Cut the meat off the bone and slice against the grain. Garnish with toasted sesame seeds and serve.