Preheat oven to 200°C (Gas Mark 6). Split open the pitta breads and cut them into nacho-sized triangles. Transfer the cut pitta triangles onto a baking dish and toast for 12 minutes. Set them aside. 

Warm the oil in a heavy-based saucepan and cook the onion on low heat for 7 minutes, until caramelized. Lower the heat and stir in the aubergines and cook until soft. Add the paprika, cumin, coriander, salt and pepper. Add the minced beef and cook for 10-15 minutes, stirring occasionally, until cooked through. Take off the heat and set aside. 

In a heatproof bowl, combine the Greek yoghurt, ġbejniet, tahini, lemon, garlic and salt. In a smaller saucepan, pour some water, enough to come up 3cm up the sides. When the water is simmering, reduce heat to low and place the yoghurt-filled heatproof bowl over the saucepan (bain marie). Using a whisk, beat well until the mixture is warm and smooth. Take off the heat. 

On a large plate, arrange the pitta triangles and top them with the beef and aubergine mixture. Pour the yoghurt mixture over the beef and aubergine. Top with the cranberries, pistachios and mint. Serve.