Soak the poppy seeds in warm water for at least 30 minutes; grind to a fine paste and keep aside.
In a bowl, beat the hung curd to soften and add ginger, garlic, mace, black pepper and red chilli powder; mix to make a marinade.
Marinate the chicken pieces in this and refrigerate for at least 6 hours or longer if time permits.
Bring the chicken to room temperature.
Heat oil in a wok or deep pan and add the chicken pieces without the excess marinade. Lightly fry the chicken pieces on both sides for about 2 minutes.
Add the rest of the marinade along with sugar and mix well to combine. Cook uncovered on low to medium heat till you can see the oil bubbling at the sides. Do not add any water.
Add the poppy seed paste along with saffron milk; stir well and continue cooking till the chicken is done.
Once the chicken is almost cooked, adjust the consistency of the gravy to suit your preferences. If dry, add a bit of water to loosen up and if too watery, yank up the flame to thicken up the gravy.