Heat the oil in a saucepan over a medium heat and cook the onion for 7 mins until beginning to soften. Turn the heat up to high, tip in the potatoes and fry for 3 mins until the potatoes are starting to colour. Add the garlic, ginger paste, ground coriander, cumin, turmeric, chilli powder and a pinch of salt. Mix well, then stir in 100ml water.

Gently stir in the chickpeas and tomato purée. Reduce the heat to a simmer and cook for 5 mins to reduce the liquid a little. Season, then stir in the fresh ginger and half the coriander. Taste for seasoning.

Sprinkle over the garam masala, chilli and remaining coriander leaves, then serve in bowls.