Prepare the fried onions (birista): Heat 100ml (about 7 tbsp) of oil or ghee in a heavy-bottomed pan or pot over medium heat. Add the thinly sliced onions and fry, stirring frequently, until they are deeply golden brown and crisp. This process can take 20-30 minutes. Be patient and do not rush, as burnt onions will impart a bitter taste. Once golden, remove the onions with a slotted spoon and drain them on paper towels. Reserve the infused oil for later use.

Prepare the rice: Rinse 500g (4 cups) of basmati rice under cold running water until the water runs clear. This removes excess starch and prevents the grains from clumping. Soak the rinsed rice in plenty of water for at least 30 minutes. This helps the grains elongate and cook evenly. Meanwhile, in a large pot, bring 2 liters (8.5 cups) of water to a rolling boil. Add the whole spices for rice (cardamom, cloves, cinnamon, bay leaf, star anise) and 1 tsp (5g) of salt. Drain the soaked rice and add it to the boiling water.

Cook the rice partially: Cook the rice for about 5-7 minutes, or until it is about 70% cooked (al dente). The grains should be slightly firm in the center. Do not overcook, as it will finish cooking with the chicken or vegetables. Immediately drain the rice in a colander, discarding the water. You can reserve a little of the spiced water if you prefer. Remove the larger whole spices if desired for a cleaner presentation.

Marinate the chicken or prepare vegetables: In a large bowl, combine the chicken pieces or chopped vegetables with 250ml (1 cup) of plain yogurt, ginger-garlic paste, chopped green chilies, turmeric powder, red chili powder, coriander powder, garam masala, 1 tsp (5g) salt, and the whole spices for the marinade (cardamom, cloves, cinnamon, peppercorns). Add half of the chopped fresh mint and cilantro leaves. Mix everything thoroughly to ensure the chicken or vegetables are well-coated. Let it marinate for at least 30 minutes at room temperature, or for 1-2 hours in the refrigerator for deeper flavor.

Cook the chicken or vegetables: Heat 50ml (about 3.5 tbsp) of the reserved infused onion oil (or fresh oil/ghee) in a heavy-bottomed pot or Dutch oven over medium-high heat. Add the marinated chicken or vegetables (including the marinade). Cook for 5-7 minutes, stirring occasionally, until the chicken is lightly browned or the vegetables are slightly tender and the oil starts to separate from the mixture. If using vegetables, you may need to add a splash of water (about 60ml / 1/4 cup) to prevent sticking and ensure they cook through later.

Assemble the Biryani: In the same pot used for cooking the chicken/vegetables (or a clean, wide, heavy-bottomed pot), spread the cooked chicken or vegetable mixture evenly at the bottom. If you cooked the chicken/veg in a separate pot, transfer it to the biryani pot now. Sprinkle the remaining chopped mint and cilantro leaves over the chicken/vegetable layer. Scatter about half of the crispy fried onions over this layer. Drizzle 1 tbsp (15ml) of lemon juice over it.

Layer the rice: Gently spread the partially cooked basmati rice evenly over the chicken/vegetable and herb layer. Ensure the rice covers the base mixture completely. Try to create a fluffy layer, avoiding pressing it down.

Add saffron milk and remaining fried onions: Drizzle the soaked saffron milk mixture evenly over the top layer of rice. Sprinkle the remaining crispy fried onions over the saffron-infused rice. You can also drizzle the remaining 2 tbsp (30ml) of reserved infused onion oil (or fresh oil/ghee) over the top for added aroma and moisture.

Seal and steam the Biryani (Dum cooking): Cover the pot tightly with a lid. To create a good seal, you can place a piece of aluminum foil over the pot before putting on the lid, or use a dough made from flour and water to seal the edges of the lid to the pot. This traps the steam inside, allowing the rice to cook fully and absorb all the aromatic flavors. Place the sealed pot on the lowest heat setting on your stovetop. Cook on 'dum' (slow steam) for 20-25 minutes.

Rest and serve: Once the cooking time is up, turn off the heat and let the biryani rest, undisturbed, for at least 10-15 minutes. This allows the flavors to meld and the rice to become perfectly fluffy. To serve, gently fluff the rice from the sides using a fork or spatula, ensuring you get both the rice and the chicken/vegetable layers from the bottom. Serve hot, optionally with raita (yogurt dip) or a fresh salad.