Halve the zucchini lengthwise and score the the cut side in a crosshatch pattern, going about 1/3 of the way through the zucchini but not cutting all the way through.
Salt the cut side of the zucchini and leave for 10 minutes to draw out moisture.
Then, pat the zucchini dry with paper towels.
To a cast iron pan over medium high heat, add just enough oil to coat the pan. Once oil is shimmering and hot, add the zucchini cut side down. Cook about 5 minutes, until golden brown, not burnt!
Transfer the cast iron pan with the zucchini into the oven. Roast zucchini for 20 minutes or until soft (depending on size of your zucchini).
While zucchini are roasting, prepare the glaze. Combine all the glaze ingredients in a small bowl.
Remove pan from the oven. Flip the zucchini over so the cut sides are face up. Brush the zucchini with the glaze and place the pan back in the oven. Set the oven to broil and cook for another minute or so until the glaze has caramelized. Remove from the oven, and let cool for 5 minutes. Top with sesame seeds and scallions. Enjoy!