Wash and soak basmati rice for 30 minutes.
In a bowl, marinate chicken with yogurt, ginger garlic paste, biryani masala, turmeric, chili powder, and salt.
Let the chicken marinate for at least 1 hour.
Heat oil in a pan and fry sliced onions until golden brown.
Remove half the onions for garnish.
Add tomatoes to the pan and cook until soft.
Add marinated chicken and cook until tender.
Boil water in a separate pot and cook rice until 70% done.
Drain the rice using a strainer.
Layer half the rice over the cooked chicken.
Add fried onions, coriander, mint, lemon juice, and saffron milk.
Add remaining rice on top and repeat garnish.
Cover and cook on low heat (dum) for 20 minutes.
Gently mix before serving and serve hot.