Dry roast the whole chilies, cumin seeds, and coriander seeds in a cast iron skillet until fragrant, about 5 minutes, turning occasionally to prevent burning.

Remove from pan and allow to cool completely.

Remove stems, membranes, and seeds from the cooled chilies.

Break the chilies into smaller pieces.

In batches, blend the chilies and remaining ingredients in a clean, dry coffee mill or mini chopper until a fine powder is achieved.

Store the seasoning mix in a covered container in a cool, dry place.