Drip some cooking oil and rub cinnamon, coriander powder and a bit of salt onto the pumpkin chunks. Roast them in the oven at 180C for 20 minutes. See *note 2.
Meanwhile, drain the water from the dried chickpeas. Then cover them with a few inches of fresh water in a saucepan, bring to a boil, then turn down the heat and cook on low heat for 20 minutes. Skip this step if you're going to use tinned/cooked chickpeas.
Save the chickpea water for making a vegan mayo (optional).
Finely chop the onion and grate the garlic and ginger.
Line up the bunch of fresh coriander and chop off the stalk part. The stalk part will be cooked first and the leaves will be added to the cooking much later.
Cut the courgettes into chunks (if you're using).
Gather the rest of the ingredients, including the spices you're using.
Heat the oil in the saucepan and add mustard seeds before the oil gets too hot. See *note 3.
Add chopped onions, and fry until the onion is soft.
Add the pumpkin pulp, and mix it with the onion.
Add garlic, ginger and coriander stalks.
Add plum tomatoes and break them up in the pan.
Add coriander powder, cumin, turmeric, curry powder, curry leaves and cayenne pepper and mix them well.
Add the courgettes chunks (if you're using them).
Add the roasted pumpkins. See *note 4.
Add coconut milk.
Turn the heat up. Once the liquid starts boiling in the pan, add chickpeas, some salt and pepper and set the heat at mid-low. Put the lid on and let it cook for another 25 - 30 minutes until the pumpkin and chickpeas are soft.
Add coriander leaves and taste the dish before serving.