Heat mustard oil in a wide, heavy-bottomed pot (a 12-inch or large cooking pot works well) over medium-high heat until it just begins to smoke.
Carefully add the whole spices and dried chillies to the hot oil. Fry for 5–10 seconds, stirring gently and watching closely, as spices like cloves and black pepper can pop. Remove the pot from the heat briefly if needed to prevent burning.
Add the sliced onions and cook for 7–10 minutes, stirring occasionally, until they turn a light golden brown. Avoid over-stirring so the onions don’t break down, and don’t let them get too dark. We want warm tint on pulao rice and the flavors to stay mild and fragrant. This step takes a bit of time and patience but it is a key step since the color of onion contributes to the color of your pulao. Avoid very dark brown or blackish onions else their smell & taste becomes too strong. Splash in a little water(¼ cup), then place the chicken pieces over the onions. Add ½ teaspoon salt, garlic paste, chopped ginger, coriander powder, green chillies, and sliced tomatoes
Now we are going to do bhuno (frying on constant heat) the chicken on medium-high heat. Cook the chicken on steady heat, stirring occasionally. This bhunai step helps the chicken sear lightly so its juices release slowly as it cooks, rather than turning watery.Continue until the chicken is no longer pink and the tomatoes have softened and broken down into the masala. Add the soaked, drained rice to the pot. Pour in warm water along with lime juice (or lemon juice). Add the remaining salt. Gently stir once or twice to combine. Make sure that all the rice grains are in water (they tend to sit on top of chicken pieces). Taste the cooking liquid and adjust salt if needed. This is the time to season your pulao perfectly! The cooking liquid should taste slightly sharp at this stage to ensure the rice cooks up flavorful.
Bring the water to a gentle boil over low-medium heat. Once you see steady bubbling, cover the pot with a tight-fitting lid, reduce the heat to the lowest setting, and cook for 10–15 minutes, or until all the water is absorbed.
Turn off the heat and let the pulao rest, undisturbed, for 15–20 minutes. This allows the rice to set and firm up. Fluffing too early can make it mushy.
Gently fluff the rice using a soft spatula or a small saucer, scooping the pulao from the side of the pot.Garnish the chicken pulao with chopped coriander leaves. Serve it sides(see notes).