Preheat your oven to 400°F (200°C). Begin by slicing the eggplants in half lengthwise. If using large eggplants, score the flesh in a crosshatch pattern without cutting through the skin. This will allow the glaze to penetrate the eggplant while cooking. Set the eggplant halves aside.

Heat 2 tablespoons of vegetable oil in a large skillet over medium heat. Once hot, place the eggplant halves, cut side down, in the pan. Cook for about 4-5 minutes until the flesh is golden brown. This step gives the eggplants a nice, caramelized base.

While the eggplants are browning, prepare the miso glaze. In a small bowl, mix together the miso paste, mirin, sugar, sake (if using), soy sauce, and sesame oil. Stir until the mixture is smooth and the sugar is dissolved. Adjust the sweetness by adding more sugar or mirin, if needed.

Once the eggplants are browned, transfer them to a baking tray, cut side up. Use a spoon to evenly spread the prepared miso glaze over the scored side of each eggplant half, making sure the glaze gets into the crevices for maximum flavour.

Place the baking tray with the eggplants in the preheated oven. Bake for 10-12 minutes, or until the eggplants are tender and the miso glaze has caramelized slightly on top. The glaze should have a glossy, golden appearance.

Once the eggplants are cooked through, remove them from the oven and let them rest for a few minutes. The resting time allows the flavors to settle, and it also makes the dish easier to handle.

To serve, transfer the eggplants to a serving plate. Garnish with a generous sprinkle of sesame seeds and chopped green onions for a pop of flavour and colour. The sesame seeds add texture while the green onions provide freshness to balance the richness of the miso glaze.

Nasu Dengaku is best enjoyed hot or at room temperature. Serve it alongside steamed rice or as part of a Japanese style meal. For a more traditional touch, pair the dish with pickles or a light miso soup. The sweet and savoury miso glaze, combined with the tender eggplant, offers a satisfying and flavourful experience of authentic Japanese cuisine.