This is a wonderful filling for burritos, a topping for Huevos Rancheros or simply great served over rice with the resulting gravy. For better flavor, prepare a day ahead.
Heat shortening in a Dutch oven, and sauté garlic until browned.
Remove the seeds and stems from the chile pods. Rinse chiles in large mixing bowl and drain.
Place moistened chiles on baking sheet and toast carefully in the oven for 5 minutes. They do not need to be completely dried out.
Remove from the oven then let cool.
Add half of the chiles into a blender, and puree with 2 cups warm water. Pour into Dutch oven with previously browned garlic and repeat with the other half of the chiles.
Add the remaining ingredients to the chile (garlic salt, oregano, onion, chile pequin)and let boil on a medium-high heat for about 30 minutes, stirring occasionally. The sauce will thicken but should remain a little soupy.
Remove from heat and cool to room temperature.
Remove the fat from the pork and cut the meat into 3/4 inch cubes. Stir pork into the chile sauce and let marinate overnight in the refrigerator.
The following day, heat oven to 300 degrees F. Use butter to coat large baking dish, so it doesn’t stick.
Add the marinated carne adovada with sauce into baking dish. Cover with aluminum foil and bake for 3 hours, stirring once at an hour and a half into baking. At 2 1/2 hours, remove foil (to thicken sauce).