Begin by setting a large pan on medium- high heat and add the oil.
When hot, add the onion, garlic, ginger, mustard seeds and cumin seeds. Allow to cook for around 5 minutes before adding the ground coriander, turmeric, chilli flakes and curry leaves and cook for another couple of minutes.
Add in the chopped tomatoes, hot vegetable stock, chickpeas and some salt and pepper. Simmer for around 15 minutes until the liquid has reduced slightly. Stir through the spinach and cook for a further few minutes until it has wilted.
Add in the lemon juice and plenty of fresh coriander.
Taste for seasoning, adding more salt, pepper and lemon if needed.