Heat the oil in a frying pan over medium high heat. When hot, stir in the chopped onion and fry for about 5 minutes or until soft and translucent.
Stir in the garlic and ginger paste and fry for about 30 seconds to cook out the rawness.
Add the ground spices followed by the tomato puree and a ladle of base sauce. Add more base as required. If the curry is looking dry, add some more. If too saucy, cook it down.
Stir in the chicken to heat through and then add the tomato, bell pepper, cucumber and chickpeas. Stir well.
Let simmer for a couple of minutes until you are happy with the consistency and then add salt to taste and sprinkle with the garam masala to serve.