Wash the aubergines and slice them lengthwise into 1/2-inch thick slabs, discarding the stem ends.

Using a sharp knife, gently score a crosshatch (diamond) pattern into the flesh of each slice, being careful not to cut through the skin.

In a small bowl, mix the vegetable oil and sesame oil, then brush this mixture generously over both sides of the aubergine slices.

Heat a griddle pan or heavy skillet over medium-high heat until it is hot and lightly smoking.

Place the aubergine slices on the griddle and cook for 4-5 minutes on each side, pressing down occasionally, until they are soft and have deep char marks.

While the aubergines cook, grind the toasted sesame seeds in a mortar and pestle until they are crushed and aromatic (or pulse briefly in a blender).

In a small bowl, whisk together the crushed sesame seeds, soy sauce, rice vinegar, mirin, and sugar until the sugar has fully dissolved.

Arrange the tender, grilled aubergine slices on a serving platter.

Spoon the sesame dressing generously over the warm aubergines, allowing it to soak into the score marks.

Garnish with the finely sliced spring onions and serve immediately while warm.