Heat oven to 180C/160C fan/ gas 4. With a sharp knife, criss-cross the flesh of the aubergines in a diagonal pattern, then place on a baking tray. Brush the flesh with 1 tbsp vegetable oil.
Mix the miso with 25ml water to make a thick paste. Spread the paste over the aubergines, then cover the tray with foil and roast in the centre of the oven for 30 mins.
Remove the foil and roast the aubergines for a further 15-20 mins, depending on their size, until tender.
Meanwhile, bring a saucepan of salted water to the boil and heat 1 /2 tbsp vegetable oil over a medium-high heat in a frying pan. Add the couscous to the frying pan, toast for 2 mins until golden brown, then tip into the pan of boiling water and cook for 8-10 mins until tender (or following pack instructions). Drain well. Serve the aubergines with the couscous, topped with the chilli and a scattering of coriander leaves.