Heat a heavy-bottomed karahi or wok or similar kind of flat bottomed wide opening pot on stove-top and add oil.
Pro tip: Always heat your wok really well before adding any oil to avoid sticking.
Optional step for Chicken Kadai recipe: Add a little oil in the hot wok, just enough to saute Onion and Bell pepper cubes, and saute the onion and green bell pepper cubes for around 2 to 3 mins on high, just until they start softening a little but still have a crunch to them. Now remove them onto a plate or bowl and set them aside to add to the dish at the end.
When the oil is hot, add turmeric powder and curry leaves and let them sizzle( be careful and step back when you add curry leaves as they splatter oil ).
Now add 1.5 teaspoons of salt to the oil and then add the chicken pieces right away and stir well. Saute the chicken pieces in the oil on high heat, without the lid for 4 to 5 minutes until they change color. Stir in between to avoid sticking and burning. The chicken will release water during this process and by cooking on high heat, we are trying to evaporate that water while sauteeing the chicken.
After 5 minutes of adding the chicken, when the chicken pieces start to look a little whitish in color, add ginger garlic paste and stir well.
After 2 mins, add cumin powder, coriander powder, red chili powder, and black pepper powder and stir well.
After a minute of sauteing the spices with the chicken, add the blanched, peeled, and diced tomatoes and mix them well with the chicken. Cover and cook for 5 minutes on medium-high heat while stirring in between. Tomatoes will release a lot of water while getting cooked.
Now open the lid, mix well, slightly increase the flame if required, and cook without the lid to evaporate all the water that is released from the tomatoes to get the curry to our desired consistency.
Check the taste and add a little more salt at this point as needed (Since we are using a lot of tomatoes, salt usage might also increase when compared to other curries).
After few more minutes, reduce the heat to medium and add the whisked yogurt and mix well. ( You can also temper the yogurt by mixing little gravy from the curry in the yogurt before adding the yogurt into the curry, this will avoid any curdling problems.)
When the chicken is almost done and gravy is close to your desired consistency, crush the Kasuri methi between your palms, add it to the curry and stir well.
Cook down while stirring in between until the oil comes out, chicken pieces are cooked to perfection and gravy is as per your desired consistency. Check the taste and adjust spices accordingly. Authentically, karahi chicken has slightly thicker gravy. But we like it with lots of gravy. You can keep it however you want.
Now in the last 2 minutes, add the thinly sliced green chili peppers, ginger juliennes, and cilantro on the top, stir lightly and cover for 2 minutes. If you are using the optional cubed onions and bell pepper then also add the sauteed onion and bell pepper cubes now in this step.
Chicken Karahi is ready to serve. Traditionally it is served with any flat-bread like naan, paratha, roti e.t.c. or basmati rice, simple pulao e.t.c