Drain and rinse 800g of canned chickpeas (undrained weight). Put them in a pan with 400ml of water, bring to a boil, then turn off the heat.
Blend 3 peeled, quartered onions, 3 garlic cloves, 1 peeled piece of ginger, 2in / 5cm long, and 2 green chilies into a paste.
Heat 1½ tablespoons of ghee in a large pan over medium heat. Fry the paste for 8-10 minutes, stirring. Season with salt.
Add ½ teaspoon of ground coriander, ½ teaspoon of ground cumin, ½ teaspoon of Kashmiri chili powder, 1 teaspoon of turmeric, and 1 teaspoon of garam masala. Cook for 3 minutes, adding chickpea water if dry.
Add 400g of canned chopped tomatoes. Cook for 5 minutes. Add the chickpeas and their water; simmer for 10 minutes.
