Line a large baking sheet with parchment paper or a silpat mat.
Combine sugar and water in a small saucepan over medium heat. Stir until uniformly mixed. Then cook, undisturbed, until mixture bubbles steadily. It will first look like there is crystallized sugar on top and like it won't get smooth, but give it time. Cook until it turns dark golden brown (at least 305°F on a candy thermometer) and, this is important, there are absolutely no crystallized white spots left (at this point it's okay to use a clean wooden spoon to stir to break any up - but make sure your spoon is completely clean and you aren't putting any unmelted sugar from the sides of the pan back into the melted sugar).
Working quickly, stir in salt and the black sesame seeds, ¼ cup at a time.
Pour onto the prepared baking sheet and spread out into a thin even layer, about ⅛-inch to ¼-inch thick. Cool for about 15-30 minutes. Tap gently with a mallet or knife to break it into pieces.
Store in an airtight container for up to two weeks. (Or fold it into ice cream)
This nutritional information has been automatically calculated, and as such, may be incomplete or inaccurate. Please reference the specific ingredients you use for the most accurate nutritional information.