150g dried New Mexico chiles (may be called Hatch chiles)
125g dried Poblano chiles (Ancho chiles)
50g dried Arbol chiles
Preheat the oven to 190 degrees F. Toast the chiles in the oven to make them more brittle and remove the excess moisture. This should take about 45 minutes, but may take up to 90 - especially for the Poblano peppers.
De-stem the chiles and add to a food processor. Grind into a fine powder. Sometimes a food processor doesn't grind fine enough so you may need to use a spice grinder or blender - depending on what gets the job done. Store in an airtight container. For best results, use within 6 months, but the flavor will still be there up to a year.