From Meryl Streep to Christopher Walken to Glenn Close, a veritable who’s who of Hollywood stars turn to one woman for haircare: Angela Cosmai. The daughter of a Brooklyn salon owner, Angela learned the craft of hair coloring from Robert Renn, a luminary colorist whose personal client list became Angela’s after his passing. Rather than implementing dramatic changes, Angela focuses on subtly enriching locks with hues that are close to her client’s original color—often restoring and correcting the damage done by other salons or gangs of four-year-olds with magic markers. To ensure hair remains as healthy as possible, she mixes her own custom, ammonia-free color formula, one of many original hair care products used in her salon. There, stylists exhibit their mastery of Angela’s techniques: applying highlights directly to roots, smoothing strands with natural keratin treatments, and lengthening locks with naturally blended extensions.