Preheat oven to 180°C (350°F)
Combine all ingredients except the eggplant into a small bowl and set aside.
Line a large baking tray, set aside.
Divide the eggplant lengthways in half. Using a sharp knife. Score, part way through. Firstly down the middle of the eggplant, then around the outside of the inner flesh, then across ways down the flesh.
In a preheated frying pan, dry fry the downside of the eggplant for four minutes, then flip and dry fry again for another four minutes. This shrinks the internal flesh, allowing the miso marinade into the eggplant.
Place the steaks onto the lined tray with the flesh facing up. Using a basting brush, marinade the eggplants with half the marinade.
Bake in the oven for 10 mins, then baste with the last of the marinade, continue baking for 10 mins.
Serve hot with mashed potatoes and green vegetables.