Preheat your oven to 200°C/Fan 180°C/Gas 6. Trim the ends off the aubergines and courgette and chop them into bite-sized chunks. Scatter them into a large roasting tin. Add a pinch of salt and pepper and 1 tbsp olive oil, and toss to coat. Slide the veg into the oven to roast for 25 mins, turning halfway, till golden.
While the veg roast, fill and boil your kettle. Tip the couscous into a heatproof bowl. Pour over 150ml boiling water. Cover with a plate and set aside to soak for 10 mins.
Peel and thinly slice the red onion and slide it into a bowl. Finely chop the parsley leaves and stalks and add them to the onion. Grate in the lemon zest and squeeze the juice from 1 half. Add a pinch of salt and stir. Set aside to quick-pickle.
Add 1 tbsp tahini to a small bowl. Peel the garlic and grate it into the bowl. Squeeze in the juice from the remaining lemon half. Tip in the yogurt, season with salt and pepper stir to combine.
Chop the tomatoes into small pieces. When the aubergine and courgette have roasted, divide half the roast veg between 2 plates, top with half of the tomatoes, pickled onion, couscous and tahini yogurt, and then repeat with the remaining veg, couscous and dressing. Top it all off with the pine nuts and serve.