Sweet potato, chickpea and feta salad with tahini dressing

Method

1. Heat the oven to 200°C/180°C fan/gas 6. Arrange the sweet potato chunks in a single layer in a large baking tray, season with salt and pepper, drizzle with olive oil, then sprinkle with za’atar/oregano. Toss to coat, then roast for 25 minutes. Put the red onion in a bowl with some salt and the juice of 1 lemon, then leave to quick-pickle.
2. Meanwhile, in a bowl, toss the chickpeas with the harissa and 1 tsp of the oil. After 25 minutes, remove the tray from the oven and push the sweet potato to one side. Add the chickpeas to the tray, then roast for 10 minutes more (see Make Ahead).
3. Toss the sweet potato, chickpeas, cucumber and herbs in a large salad bowl (or on a platter), then scatter over the feta. Drain the red onions, then scatter over the top.
4. In a bowl, mix the yogurt with the tahini and remaining lemon juice and oil, then season with salt and pepper. Serve the dressing tossed with the salad or on the side.