Vadukapuli naranga achar
Vadukapuli naranga is a large, knobbly, thick-skinned wild lemon grown in Kerala backyards, and it is ripe just in time for Onam in August–September. Cut into small cubes with its spongy white pith and mixed with green chilli, ginger, chilli powder and a sesame-oil tempering, it becomes the pale yellow pickle dabbed on the end of every sadya banana leaf, next to inji puli and mango. It is sour, bitter and fresh at once, with juicy flesh and a soft, absorbent pith that soaks up the spices. It is just as welcome with curd rice or a simple moru curry. The common mistake is leaving the bitter seeds and the tough central core in; take them out or the whole jar turns harsh. It is ready to eat after a day, once the salt has drawn out the juice and the pieces look moist and slightly translucent. Because it has fresh ginger, green chilli and curry leaves, keep it in the fridge and eat within a month. Outside Kerala, use a citron or the biggest thick-skinned lemons you can find. Chef's tip: a spoon of vinegar sharpens the pickle and helps it keep; Kerala Christian homes often add one.



