In a large bowl, combine chicken with ginger-garlic paste, Kashmiri chili powder, turmeric, coriander powder, cumin powder, crushed black pepper, yogurt, and also salt.
Mix thoroughly ensuring that each piece is well coated. Let it marinate for at least 30 minutes to 1 hour to allow the flavors to deepen.
In a small bowl, add the saffron strands to the warm milk, allowing it to steep until the milk turns a golden hue.
Heat the oil in a deep pan and then saute the whole spices for 30 secs. Now add the marinated chicken and cook until the pieces are seared about 4 to 5 minutes.
Blend the fried onions, and cashew nuts with 2 green chillies and a little milk to make a smooth paste. Add this paste to the pan and also add the saffron-infused milk and stir well.
Then cover the vessel and let the chicken cook. This would take approximately 8 to 10 minutes on low heat.
Add fresh cream into the pan, and also the mace-nutmeg powder and the garam masala powder.
Continue to cook until the chicken is fully tender and the curry is rich and creamy.
Finally, garnish with fresh coriander leaves and serve hot.