Trim, peel, and slice onions into thin half-rings (1-2mm). Separate the rings so they don't stick together.
Add onions to cold oil in a wok, ensuring they're evenly coated. Set heat to medium-high and fry, stirring frequently, until hints of golden brown appear (10-20 minutes).
Reduce heat to low and continue until light golden (2-3 minutes). Don't let them turn deep goldenโthey'll darken after removal.
Remove onions with a spider strainer, press gently, and spread on paper towels. Separate with forks. Strain and reserve the onion oil.
Biryani Masala
Toast all whole spices in a cold skillet on medium heat until aromatic and warm. Transfer to a bowl to cool.
Grind cooled spices with nutmeg, turmeric, and salt until fine but not completely pulverized. Store in an airtight container (keeps 2-3 months).
Chicken Marinade
Pull skin off chicken drumsticks at the joint, using a knife if needed. Peel and cut potatoes into 6 chunks each.
In a large bowl, season chicken and potatoes generously with salt. Add yogurt, lemon juice, ginger, garlic, green chili, biryani masala, and Kashmiri chili powder.
Add 1/4 of the fried onions, a few spoonfuls of onion oil, and sprinkles of mint and cilantro. Mix well. Marinate 4-8 hours ideally, but even 15-30 minutes helps.
Spiced Rice
Wash rice thoroughly until water runs clear. Soak in room temperature water for 30-90 minutes.
Boil 2L water with bay leaves, cinnamon, shah jeera, cardamom, cloves, star anise, peppercorns, and halved green chili. Squeeze in lemon juice and add the rind. Season generously with salt (like pasta water).
Add soaked rice and cook until 90% done with a slight al dente bite in the center (3-5 minutes). Drain and spread on a tray to steam off.
Heat onion oil in a heavy pot over high heat. Add marinated chicken and potatoes, cook stirring frequently for 5-6 minutes.
Reduce heat to low, cover tightly, and cook until chicken is almost done (10-12 minutes). The ghee and chicken fat should separate from the gravy.
Meanwhile, gently warm milk in microwave until steaming. Add saffron and let bloom. Set aside.
Taste the gravyโit should be intensely flavored and on the saltier/spicier side. Adjust salt if needed. Add 1/2 cup water if you prefer a saucier biryani.
Distribute chicken and potatoes in an even layer. Sprinkle with biryani masala, then top with half the mint, cilantro, and fried onions for this step.
Spread pre-cooked rice in an even layer on top. Drizzle with saffron milk, add small knobs of butter, then top with remaining mint, cilantro, and fried onions.
Cover with a tight-fitting lid and place an upside-down heavy pot on top. Cook on medium-high for 5 minutes. Do not open the lid!
Turn flame to low and cook for 15 more minutes. Do not open the lid! Remove from heat and rest for at least 10 minutes without opening.
To smoke: transfer biryani to a large serving platter. Melt ghee in a small heatproof bowl and place it in the center of the platter.
Light charcoal with a torch until glowing hot. Drop into the melted gheeโit will smoke immediately. Quickly cover with an upside-down bowl to trap the smoke. Infuse for 3-4 minutes, then serve.
Notes
Chop a full bunch each of mint and cilantro at the startโyou'll use them across multiple steps.
For best results, use aged basmati rice with super long grains.