Choose a substitute that matches your goal: pasilla for closest dried-chili flavor, chipotle for smokier heat, or cocoa/chili blend for ancho-like sweetness.
Measure using the listed ratio (start slightly low for smoky/hot options like chipotle).
Bloom the spice in a tablespoon of oil for 20–30 seconds (or stir into a warm sauce) to reduce harshness and improve integration.
Taste, then adjust: add small pinches for heat, and add a pinch more cocoa or a tiny pinch of sugar to mimic ancho’s dried-chili sweetness if needed.