Place trimmed artichokes in a steamer basket and steam for 40-45 minutes, until leaves pull away from the whole artichoke easily. Remove from steamer pot.
When cool enough to the touch, slice artichoke down the middle lengthwise. At this point, you can remove the “hair” and purple leaves that fill the middle of the artichokes with a spoon. They serve no purpose and have little “meat” on them. (I grilled the artichokes with that part still on just for photos because it’s so pretty!)
Heat grill pan or grill to medium heat. Whisk together all the ingredients for the glaze then use a brush to brush half the glaze on the inside of the artichoke and into the leaves. Place cut side down on the grill plan then brush the rest of the glaze on the outside. Cook artichokes for 4-5 minutes per side, until grill marks are visible. Top artichokes with sesame seeds.
Mix all ingredients for sriracha dip together.
To eat: remove leaves and dip the ends in the mayo and scrape off with your teeth. See exact photos here if you have never ate an artichoke.