Score the cut face of each eggplant half in a diamond pattern, cutting halfway through the flesh but not piercing the skin.

Sprinkle the cut faces with the salt and rest for 15 minutes. Blot dry with paper towel.

Whisk the miso, mirin, sake and sugar in a small bowl until smooth.

Brush the cut faces with oil. Heat the grill to medium-high. Grill cut-side up for 8 minutes until the flesh begins to soften.

Brush a generous layer of the miso glaze over the cut faces. Grill another 4 minutes.

Brush a second coat of glaze. Increase grill heat and finish for 1 to 2 minutes until the top is dark amber and bubbling. Watch closely; the glaze can burn quickly.

Scatter with sesame seeds and spring onion. Serve immediately with cold sake or steamed rice.