1 medium butternut squash (about 750g/1lb 10oz), peeled, deseeded and cut into 2.5cm/1in pieces
1 onion, finely chopped
400g tin chickpeas, drained and rinsed
400g tin chopped tomatoes
1 tsp dried chilli flakes
1 tsp ground cinnamon
1 tsp ground cumin
1 tsp salt
2 tbsp vegetable or sunflower oil
plain yoghurt (any variety), to serve (optional)