Step 1: Prepare the Japanese Eggplant. Wash and trim the ends of the Japanese eggplants. Slice them into 1/2-inch thick rounds or on the diagonal into 1-inch thick pieces. If you prefer, you can also halve them lengthwise and score the flesh in a crosshatch pattern. Arrange the sliced eggplant on a few layers of paper towels to absorb any excess moisture while you prepare the glaze. You generally don’t need to salt Japanese eggplant, but a quick pat dry ensures a better sear.
Step 2: Whisk Together the Miso Glaze. In a small bowl, combine the white miso paste, mirin, soy sauce, granulated sugar, and 1 tablespoon of sesame oil. Whisk until completely smooth and the sugar has dissolved. Taste the glaze – it should be a balance of sweet, salty, and umami. Adjust any component to your preference.
Step 3: Cook the Eggplant. Heat about 1-2 tablespoons of sesame oil in a large non-stick pan or cast-iron skillet over medium-high heat. Once hot, add the eggplant slices in a single layer, making sure not to overcrowd the pan. You may need to work in batches. Cook for 3-4 minutes per side, or until the eggplant is tender and beautifully browned. The eggplant will absorb the oil, so add a little more if needed between batches.
Step 4: Glaze the Eggplant. Once all the eggplant slices are cooked and tender, return them all to the pan. Reduce the heat to low. Pour the prepared miso glaze evenly over the eggplant. Gently toss or spoon the glaze over each piece, ensuring they are well coated. Continue to cook for another 1-2 minutes, allowing the glaze to thicken slightly and adhere to the eggplant. Be careful not to let the glaze burn; keep the heat low and stir gently.
Step 5: Serve and Garnish. Transfer the glazed Japanese eggplant to a serving platter. Sprinkle generously with toasted sesame seeds and fresh chopped green onions for a burst of color and freshness. Serve immediately as a side dish or a light main.