Place an oven rack on top of a gas burner. Make sure you're cooking in a well-ventilated area to avoid breathing in the fumes that will generate when charring the chiles. Place the chiles on the rack and char over an open flame. (you can also char the chiles in a cast-iron skillet over high heat.) Using tongs, turn the chiles as they char. The chiles will puff up and turn completely black. Remove from the heat and cool.

Discard the stems from all the chiles as well as the seeds from the anchos. Add the chiles and all the remaining ingredients to a food processor or blender and mix until fully incorporated. Use immediately or transfer to a container and refrigerate for up to 4 weeks (it never lasts that long).