Heat oil on medium-high heat.
Add onions and cook until slightly golden
Add ginger-garlic and cook for 15-20 sec
Add all powdered spices and stir 20–30 seconds only
Add tomato puree (or paste) and cook till oil separates
Add chicken. stir & sear 3–4 minutes
Add coconut milk + ¾ cup hot water
Simmer covered 15–18 minutes
Finish with garam masala. Optionally add lemon juice