Marinate the chicken in ginger garlic paste, kashmiri chili powder, red chili powder, and salt for at least 2 hours or overnight.
Heat oil in a pan and add the mustard seeds. When they start spluttering, add the curry leaves.
Next, add in the onion. Fry till the onion turns translucent.
Add the coriander powder, green chili, and roasted cumin powder. Saute for a minute.
Add the tomatoes and marinated chicken. Close the lid of the pan and cook on low flame till the tomato is cooked. Stir occasionally to prevent the masala from getting burnt.
Cook till all the water from the chicken has dried up. Roast the chicken well stirring frequently.
Switch off the flame when the masala has been coated well with the chicken. Serve hot garnished with coriander leaves and lemon wedges.