Ají Verde

Ají verde is the table sauce of pollo a la brasa, the rotisserie chicken developed in Lima in the 1950s; the chicken is the documented innovation, while the green sauce grew up around it as its standard accompaniment rather than as a dish with its own dated origin. Its character comes from two native ingredients at the heart of Peruvian cooking: ají amarillo, the fruity yellow-orange chili, and huacatay, the strongly aromatic black-mint of the Andes used since pre-Hispanic times. The creamy, mayonnaise-and-cheese form is the modern restaurant style; rustic versions are simply herbs, chili, garlic and oil pounded or blended together. Outside Peru it is often called simply Peruvian green sauce.

Pale jade green and pourable, it looks cool and tastes lively. The first note is herbal and fresh — cilantro and the distinctive, almost mint-meets-marigold scent of huacatay — then the fruity warmth of ají amarillo builds into a gentle, lingering heat. Garlic and lime keep it sharp, while the cheese and mayonnaise lend a creamy roundness that tames the chili and clings to whatever it coats. Against hot, smoky rotisserie chicken and crisp fries, it is bright, rich and a little addictive, the part of the plate people ask for more of.

This is a raw, cold emulsion: the blender shears the oil and the fat in egg yolk and mayonnaise into tiny droplets suspended in the watery herb-and-lime base, giving a stable, creamy sauce without any cooking. The fat does double duty — it carries the chili's fat-soluble flavor and capsaicin and buffers the heat on the palate, which is why the creamy version tastes milder than a watery one of the same chili. Keeping everything cold and blending briefly protects the chlorophyll and volatile oils in the cilantro and huacatay, so the sauce stays vivid green and fragrant; over-blending warms it and can turn it dull and bitter.