1 Cut the chiles open and remove stem and seeds: Working on one chile at a time, use a paring knife to cut a slit all the way down one side of a chile. Open up the chile and remove the stem and seeds. Remove as much of the veins as you can.
Reserve a few of the seeds or veins for adding later if you want added heat.
Note when working with chilies, either wear protective gloves or wash your hands very thoroughly with soap and warm water after handling the chilies. Do not touch or rub your eyes if you have been handling chili peppers.
2 Heat the chiles on a skillet: Heat a large skillet on medium heat. Flatten out the dried chilies as well as you can and place on the skillet to heat.
Press down on the opened chilies and leave for a few seconds. Turn the chilies over and heat a few seconds more.
You do not want to toast or burn the chilies! If they burn, they’ll turn bitter. Just heat them enough to draw out more of their flavor.
3 Soften the chiles in hot water: Add the chilies to a small saucepan and add enough water so that they are just covered. Bring to a boil. Remove from heat and let sit for 10 minutes, until the chilies have softened and plumped up.
(OR pour place the chilies in a small saucepan and pour boiling water over them to cover. Let sit for 15 minutes, until softened.)
4 Purée with garlic, seasonings, water or poaching liquid: Reserving the soaking water, remove the chilies from the pan and place in a blender. Add the garlic, salt, ground pepper, ground cloves, and 1 1/2 cups of the soaking liquid (taste the soaking water first, if it seems bitter, use plain water instead).
Purée for 2 minutes, until the sauce is completely smooth. Taste the sauce and adjust the seasoning. If you want more heat, add in a few of the seeds or veins and purée some more. Add more salt if needed.
5 Strain through sieve into a skillet, simmer: Pour the sauce through a sieve into a skillet. Add a tablespoon of olive oil to the sauce.
Bring to a simmer and reduce heat to maintain the simmer, cook for 10 minutes. Skim off the foam.
Remove from heat. Use immediately or pour into a glass jar (plastic will get stained) and refrigerate.