Curry leaf

Curry leaf is the pinnate foliage of Murraya koenigii, a slender understory tree of the Rutaceae family native to the foothills of the Himalayas, the Deccan plateau and the wet zones of Sri Lanka. The leaves come in odd-pinnate sprays of eleven to twenty-one lance-shaped leaflets, each one roughly four centimetres long, matte on top and paler beneath. It is crucial to separate this plant from the unrelated Mediterranean «curry plant» Helichrysum italicum and from commercial curry powder blends — botanically, culinarily and aromatically, they share nothing. The leaf's aroma is driven by carbazole alkaloids, principally mahanimbine, mahanine and koenigicine, alongside alpha-pinene, sabinene, beta-caryophyllene and small amounts of linalool. Those carbazoles are unique in the kitchen and give the leaf its warm, almost-nutty tobacco-asafoetida edge. The canonical technique is the tadka or tempering: a ladle of hot ghee or coconut oil, black mustard seeds that pop within seconds, a pinch of urad dal, a few dried chillies, then a fistful of curry leaves thrown in whole — they shiver, blister and release their scent over sambar, rasam, dosa chutney, upma, poriyal and lemon rice. In Sri Lankan kari patta cookery the leaves stay in the finished dish.