New Mexico dried chiles have a moderately spicy heat. If you can't find them, you can try substituting ancho or dried California chiles. Make this red chile sauce up to three days ahead, and refrigerate until you're ready to use it.
5 dried red New Mexico chiles (about 1 1/4 ounces)
Remove stems and seeds from chiles; coarsely chop. Place chiles in a spice or coffee grinder; process until finely ground to measure 1/4 cup.
Heat oil in a medium saucepan over medium heat. Add onion and garlic to pan; cook 3 minutes or until onion is tender, stirring frequently. Add ground chiles; stir well. Stir in 1 cup chicken broth. Add the remaining 1 cup chicken broth, 2 cups water, dried oregano, and salt; bring to a boil. Reduce heat, and simmer until reduced to 3 cups (about 20 minutes), stirring occasionally.
Sprinkle masa harina over chile mixture; stir well. Bring to a boil. Cook for 1 minute or until slightly thick; remove from heat. Let stand 10 minutes. Place half of the chile mixture in a blender. Remove the center piece of blender lid (to allow steam to escape); secure blender lid on blender. Place a clean towel over opening in blender lid (to avoid splatters). Process until smooth. Pour into a large bowl. Repeat procedure with the remaining chile mixture.