In a blender or food processor, combine all the ingredients for the jerk marinade and blend to a smooth paste. You can add little water to help with blending.
In a bowl, add chicken, salt, 1 cup fried onions and the jerk marinade. Mix well to coat evenly and set aside for 1 hour. After1 hour, mix 3 tablespoon yogurt to the marinated chicken and set aside overnight or 2 hours.
Rinse the basmati rice in cold water until the water runs clear. Soak the rice in water for 30-45 minutes.
Heat 1 cup milk and add a pinch of saffron.
In a large pot, heat 4 tablespoons of oil over medium heat and add the caraway seeds. After the caraway seeds crackle, instantly add the marinated chicken and cook for 15 mins.
In a separate large pot, add 6-8 cups of water and bring it to a boil. Add the spices and let it boil for another 2 mins. Drain the rice and add it to the pot. Cook the rice until 70 -75% done. Use a spider strainer to drain the rice.
Add 2 layers of remaining fried onions, saffron milk and rice. Cover with a silver foil and lid. Set the pot on low heat and cook for another 15 mins to allow the aroma to stay it in.
Remove the pot from the heat and let it rest covered for another 15 mins to allow the flavors to further develop. Gently lift the rice with a spatula to reveal the layers of fluffed rice with chicken.
Garnish with the remaining fried onions and serve the hot biryani with a cool cucumber or boondi raita.