Fry chopped onions (sliced or diced depending) in oil or butter.
Add finely chopped (mashed) garlic. Add ginger (mashed or sliced depending). Add chopped green chilli. Add cumin (or cumin powder). Cook until unions opaque.
Add gram massala and cook. Add termeric and stir in all the indredients. Add chopped tomatoes (amount depends on how much sauce is required). Add water if required. Simmer. Add herbs (coriander).