Create the Miso Bed: In a glass container or non-reactive bowl, combine the miso, mirin, grated ginger, and garlic.
Stir until everything is well combined to create your 'misodoko' or pickling bed.
Set aside.
Prepare the Eggplant: Cut the eggplant into ¼ inch / 5 mm thick rounds or half-moons.
Place them in a large bowl, cover with water, and stir in the salt.
Place a plate directly on top of the eggplant to keep it submerged and let it sit for 10 minutes.
Drain and Dry: Drain the salted water from the eggplant.
Rinse the slices thoroughly under cool water to remove excess salt, then pat them completely dry with a clean kitchen towel or paper towels. This step is crucial for a crisp texture.
Pickle the Eggplant: Add the dry eggplant slices to the miso mixture. Use your hands or a spoon to toss and ensure every piece is thoroughly coated in the miso paste.
Ferment and Enjoy: Cover the container. For a light, crisp pickle, let it sit at room temperature for 4 hours. For a deeper, more intense flavor, transfer the covered container to the refrigerator and let it pickle for up to 2 days.
Serve: When ready to eat, remove the desired amount of eggplant from the miso. Gently rinse off the excess miso paste under cool water and pat dry before serving.
Don't skip salting and weighting the eggplant. It removes excess water and bitterness, ensuring a crisp texture and preventing a watery final pickle.