Prepare the eggplant: Slice each eggplant in half, lengthwise, then lightly score the flesh in a crosshatch pattern. This helps it cook evenly and allows the miso glaze to soak in.
Pan-fry the eggplant: Heat a little oil in a pan over high heat, then place the eggplant cut-side up so the skin side touches the pan. Let the skin brown and crisp for a few minutes.
Flip and cover: Turn the eggplant halves over so the cut side faces down, cover with a lid, and cook for another 3 to 4 minutes until the inside is soft and fully cooked.
Mix the miso glaze: While the eggplant finishes cooking, whisk together miso paste, mirin, sugar, and sake in a small bowl until smooth and glossy.
Brush on the glaze: Line a baking tray with foil, place the cooked eggplant halves skin-side down, and generously brush the miso glaze over the entire surface.
Broil until caramelized: Place the tray under the broiler for about 4 minutes, or until the glaze is bubbling and caramelized around the edges.
Garnish and serve: Finish the miso-glazed eggplant with a sprinkle of sesame seeds, then serve hot while the glaze is still beautifully glossy and flavorful.