Rinse any dirt off the chile pods. Gently toast dried whole chile pods in a heavy skillet over medium heat until they are warm and release their fragrance, 1 to 2 minutes per side. Be very careful to prevent any burning. Remove the chiles from the skillet immediately. When cool enough to handle, break each chile pod into several pieces and discard stem and seeds. Wearing rubber gloves is highly recommended.

Heat the chicken broth in a medium sized saucepan with the chiles submerged. Bring to a boil and then reduce heat to low and simmer for about 10 minutes.

Warm the oil in a large saucepan over medium heat. Add the onion and garlic, and sauté several minutes until the onion is limp. Add the flour and spices and continue to cook until the flour becomes fragrant.

Combine the chiles, chicken broth, onion, garlic, and spices in the blender and blend until smooth. You may have to do this in several batches.

Return blended sauce to the saucepan and heat until it just starts to bubble. Reduce the heat to medium-low and simmer for a total of 20 to 25 minutes.

After about 15 minutes, taste the sauce and adjust seasonings. When ready, the sauce will be cooked down enough to coat a spoon thickly but still drop off of it easily. Use warm or refrigerate for later use.