Place the squash on a baking tray together with the onion wedges. Sprinkle over 3 tbsps of the oil and the garam masala. Season with salt and plenty of freshly ground black pepper to taste.
Bake for 25-30 minutes then add the pumpkin seeds and bake for a further 10 minutes, until the squash is tender. Remove from the oven and set aside.
Place the chickpeas on a separate baking tray with the remaining oil and chilli flakes. Season to taste with plenty of salt and black pepper and mix well to coat the chickpeas.
Bake for 8-10 minutes until the chickpeas begin to sizzle and some turn brown and crisp. Remove from the oven and put to one side.
To make the dressing heat the oil in a small saucepan over a moderate heat. Add the garlic, ginger, cumin, turmeric, mustard seeds and honey and cook for one minute until fragrant. Add the lemon juice and zest and season with salt to taste.
Put the squash and chickpeas into a large serving dish, scraping in any juices. Add the chopped coriander and spoon over the dressing.