Sweet potato, chickpea and feta salad with tahini dressing

Ingredients

• 3 sweet potatoes, peeled and cut into bite-size chunks
• 3 tbsp olive oil, plus extra to drizzle
• 2 tsp za’atar or ½ tsp dried oregano
• 1 red onion, sliced
• Juice 2 lemons
• 400g tin chickpeas, drained and rinsed
• 1 tsp rose harissa (we like Belazu)
• ½ cucumber, halved lengthways, deseeded, then cut into chunks
• 20g fresh flatleaf parsley, chopped
• 15g fresh mint, roughly chopped
• 15g fresh dill, roughly chopped
• 100g feta, cut into chunks
• 4 tbsp greek yogurt
• 1 tbsp tahini