Once you see the oil floating on top or the sides of the chicken curry, it’s ready. This process usually takes around 45 minutes for bone-in chicken, and around 30 minutes for boneless chicken pieces. The masala has had enough time to cook, and turn into a gravy base. It’s important to add a sufficient amount of oil for the gravy base to come together. If you add less oil, the chicken curry will be healthier yes, but the gravy won’t be as rich and vibrant.