Coarsely grind 1 tsp cumin seeds, 1 tbsp coriander seeds, 1/2 tsp nigella seeds, 1/2 tsp fennel seeds, and 1/4 tsp mustard seeds to make the achari masala.

Make deep slits across the whole chicken so the marinade can penetrate the meat.

Combine lemon juice, red chili powder, 1 tsp ground coriander, ground cumin, 1/2 tsp garam masala, chili flakes, 1 tsp salt, black pepper, yellow food coloring, chicken tikka masala, and the achari masala in a bowl.

Rub the spice marinade thoroughly over and inside the slashed chicken. Cover and refrigerate for 120 min.

Pour about 4 cups of water into a large pot and bring it to a simmer over medium-high heat.

Set the steamer basket over the simmering water and place the marinated chicken inside. Cover the pot.

Steam the chicken over medium-high heat for 20 min, maintaining enough water below the basket to collect the flavorful chicken drippings.

Remove the steamed chicken and reserve the liquid with its drippings in the pot as chicken yakhni stock for the pulao.

Brush the steamed chicken with about 1 tbsp of the neutral cooking oil. Place it on an oven-safe tray.

Grill the chicken in a hot oven at 220°C / 425°F for 10 to 15 min. Cook until the skin is crisp and browned and the thickest part reaches 74°C / 165°F.

Heat the remaining neutral cooking oil in a second large pot. Add 1 tsp cumin seeds and fry until fragrant.

Add the sliced onion and cook until lightly golden. Stir frequently to prevent burning.

Add the chopped tomato, 1 tsp ground coriander, and 1/2 tsp garam masala. Cook until the tomato softens.

Add the green chili, remaining 2 1/2 tsp salt, reserved chicken yakhni stock, and saffron steeped in 1/4 cup water. Bring the liquid to a boil.

Add 2 1/2 cups basmati rice to the boiling yakhni. Cook uncovered until most of the liquid has evaporated.

Sprinkle the remaining 1/2 tsp garam masala over the rice. Cover the pot tightly.

Steam the covered pulao over very low heat for 10 min. Rest it off the heat for 5 min before fluffing.

Spread the yakhni pulao onto a serving platter. Place the crisp steam-roasted chicken on top and serve hot.