Pork and potato tacos in guajillo chile sauce (tacos de cazuela)

Pull the stems off the guajillo chilies, tear them open and shake out the seeds; pull out the veins for less heat.

Open each into a flat piece and toast on a griddle or dry skillet at about medium, pressing down, a couple of seconds, then flip and press another 10 seconds or so until it crackles and lightens.

Cover the chilies with hot tap water, weight them with a heavy plate to keep them submerged, and leave about 30 minutes until soft and pliable.

Drain off the soaking liquid; puree the chilies smooth in a food processor with canned tomatoes, chopped garlic and some liquid.

Brown the pork shoulder, cut in small pieces, in a heavy pot in two batches so it browns evenly without stewing; return all of it to the pot.

Pour the chili puree through a strainer into the pot; only skin should be left in the strainer.

Stir over a fairly high flame six to eight minutes until reduced to the consistency of tomato paste; cover with a spatter screen if it jumps.

Add water and salt and stir; reduce to medium-low, set the lid ajar and simmer about 45 minutes to tenderize the pork.

Add the diced potatoes about halfway through the simmer.

Serve in the corn tortillas with cilantro sprinkled over.