How To Prepare Poblano Pepper:
Roast the poblano. This can be done by either impaling one end of the pepper on a long kitchen fork and exposing it directly to an open flame (if you have a gas stove), or by roasting it on a tray under a preheated broiler.
Roasting them over an open flame is the traditional way to cook and char poblanos, though roasting them in a broiler is a significantly more convenient way to prepare multiple poblanos simultaneously.
Whichever roasting method you choose, make sure to turn the peppers over every few minutes to ensure even cooking. Depending on the size of the peppers you’re roasting, they’ll need from 6 to 10 minutes to fully cook. The flesh inside should become very soft, and while the skin should have large char marks, it should not be completely burnt.