Preheat oven to 425°. Cut eggplant in half lengthwise to expose the flesh. Score eggplant slices in a crosshatch pattern and coat completely with sesame oil. Roast the eggplant on a baking sheet cut side down, until very tender and the skin is beginning to shrivel, about 15-20 minutes. Remove from the oven, carefully turn the eggplant over and pre-heat the broiler.
While the eggplant is roasting, make the giner-miso glaze. Whisk all miso-ginger glaze ingredients together in a saucepan over very low heat for a few minutes; just until all ingredients are combined well together.
Brush the miso glaze on the cut surface of the roasted eggplant and broil on the same sheet/tray as used above, until golden and charred, about 4–5 minutes.
Remove from oven and sprinkle garnishes, sesame seeds, scallions, microgreens, and/or flaky sea salt.