Step 1

Fry onion in 120ml oil in a saucepan over medium-high heat, stirring occasionally, until golden (6-8 minutes). Transfer to a bowl and cool. Dry-roast spices, chilli and bay leaf over medium heat, then pound with a mortar and pestle to a fine powder. Add to onion along with yoghurt, herbs, ginger, garlic and 2 tsp sea salt and mix well. Add chicken, stir to coat, cover and refrigerate overnight to marinate.

Step 2

Spread chicken mixture in the base of a heavy-based casserole with a tight-fitting lid. Bring rice, 20gm butter, remaining oil and enough well-salted water to cover by 2cm to the boil in a saucepan over medium-high heat. Drain and spread over chicken.

Step 3

Bring milk, saffron and remaining butter to the simmer in a saucepan over medium-high heat, then pour over rice, cover with foil, then the lid. Cook over low heat until rice is fluffy and chicken is cooked through (50 minutes-1 hour). Stand for 15 minutes without removing the lid, then serve hot, scattered with fried shallots and coriander sprigs, and with lemon wedges to the side.