The makrut lime is a small, dark-green citrus wrapped in a knobbly, deeply wrinkled rind, grown across Southeast Asia less for its meagre juice than for the extraordinary perfume of its zest. Where an ordinary lime is sharp and piney, makrut is floral, resinous and almost cologne-like — a bright, aromatic lift that defines Thai, Lao, Cambodian and Indonesian cooking. The fruit yields little sour juice and a thick, bitter peel, so cooks prize the intensely fragrant zest, which is pounded into curry pastes and grated over relishes and soups.