Put the chopped onions and 1 green chilli in a bowl with the malt vinegar and set aside.
Make insertions/slits on the chicken legs.
Dry roast the spices in a pan.
Put the spices in a mortar and pestle and grind into a nice powder.
Dry roast the aromatics- ginger, garlic and green chillies.
Mix this in with the powder and grind into a nice paste.
Add some mint leaves, jaggery and juice of 1/2 a lime to this spice paste.
Pour a few teaspoons of ghee onto the chicken and rub in the marinade. Put into the fridge for 2 hours or so. Then bring the chicken to room temperature and season well.
Heat a tava with some oil and sear the chicken on a high flame till nicely colored, turn down the heat and fry gently, deglazing with a little water to prevent the masala from burning, until it's a nice golden brown colour.
Baste with ghee/butter and lime juice and cook till the chicken is tender and cooked perfectly. Scatter over some fresh coriander and serve with the sirca pyaaz, green chillies and lime wedges.