Rinse 500 g basmati rice until the water runs mostly clear, then soak it in water for 20 to 30 minutes.

Drain the soaked basmati rice thoroughly and set it aside while preparing the masala.

Slice the onions, chop the tomatoes and potatoes, slit the green chilies, and chop the coriander leaves leaves.

Heat 120 ml cooking oil in the large heavy-bottomed pot over medium heat, then fry the sliced onions until light golden.

Add cumin seeds, whole black peppercorns, whole cloves, curry leaves, green chilies, and ginger garlic paste to the onions.

Cook the aromatics for 2 to 3 minutes, stirring constantly until the ginger garlic paste smells cooked and fragrant.

Add the chopped tomatoes, chili powder, turmeric powder, and half of the biryani masala, then stir to coat the tomatoes.

Add a small splash of water and cover the pot, then cook the masala until the tomatoes soften and oil rises to the surface.

Add the chopped potatoes and 120 ml water, then cover and cook over medium heat until the potatoes are partly tender.

Crumble in the chicken stock cube and add the remaining biryani masala with the coriander leaves leaves, then mix well.

Add the drained basmati rice to the potato mixture and gently fold until every grain is coated in masala.

Pour in the remaining water and add salt, then stir once gently to distribute the seasoning.

Bring the pot to a boil over high heat, then reduce the heat to medium and cover it tightly.

Cook covered until the visible water has evaporated and steam holes appear on the rice surface, about 12 to 15 minutes.

Place the covered pot on a flat griddle over very low heat and steam for 10 to 15 minutes until the rice and potatoes are fully tender.

Rest the Tahiri for 5 minutes, then gently fluff it and serve hot with salad, raita, or kebabs if desired.