Twice baked feta potatoes with za'atar pesto

Name: Twice baked feta potatoes with za'atar pesto
Prep time: 20 min
Cook time: 20 min
Total time: 40 min
Cuisine: Middle Eastern
Ingredients: 2 jacket potatoes (500g); 2 sweet potatoes (600g); 60ml olive oil; 50g Greek-style yoghurt; 60g spring onions, plus 2 tbsp extra sliced; 2 tsp cumin seeds, toasted and roughly crushed in a pestle and mortar; 1 tsp chilli flakes; 2 tsp dried oregano; 100g Greek feta, roughly crumbled; 100g lancashire cheese or mature cheddar, roughly grated; Salt and black pepper; 500ml sunflower oil; 1 onion, thinly sliced on a mandolin (180g); 1 tbsp cornflour; 1 large lemon; 3 tbsp za’atar; 20g coriander, roughly chopped; 1 garlic clove, roughly chopped; 40g pine nuts, lightly toasted; 90ml olive oil