Preheat the oven to 190°C. Halve the butternut and remove the seeds. Cut into roughly into 2-3cm squares (you don't need to peel it) and chuck on a roasting tray. Sprinkle 2 teaspoons of the madras curry powder, then the cumin, coriander, and chilli flakes over the pumpkin and season with some salt and pepper. Drizzle 1 tablespoon of oil over the top and mix everything together so the pieces of pumpkin are well coated in the spices and oil.
Place the tray in the oven and roast the pumpkin for about 40 minutes, or until it looks nice and tender and slightly browned around the edges.
In the meantime finely slice the red onion, and the stalks off the bunch of coriander. Finely dice the garlic and green chilli.
Heat the other tablespoon of oil in a medium saucepan and add the chopped up vegetables. Grate in the fresh ginger and then stir everything together and saute for about 10 minutes until everything is softened.
Roughly chop the tomatoes and add these to the pan with the drained chickpeas and the remaining 2 teaspoons of madras curry powder. Bring to a boil and simmer for about 20 minutes.
Once the pumpkin is roasted, remove from the oven and add to the curry. Simmer for a further 10 minutes
Finally, add the baby spinach and stir in and cook for a minute or two until it has just wilted.
Serve with some steamed basmati rice and a handful of chopped coriander leaves.