Directions
Toast the chiles: Bring 2 cups of water to boil in a saucepan or kettle. In a medium skillet over medium heat, press the chiles flat against the surface until they smell fragrant (about a minute). Do not let them blacken or they will become bitter.
Rehydrate the chiles: Transfer the toasted chiles to a small heat-proof bowl or the saucepan and cover with 2 cups of boiling water. Place a small plate or lid on top to trap the steam. Let the chiles soak for 10 to 15 minutes or until completely softened. Drain the chiles, discarding the soaking liquid.
Blend: Add the chiles to a blender along with garlic, tomatoes, tomato paste, oregano, cumin, and salt. Blend on high until completely smooth. Stream in stock and puree until completely smooth.
Simmer until thickened: Pour the pureed mixture back into the skillet and add the vinegar. Bring to a simmer over medium heat and cook, stirring occasionally, for about 10 to 15 minutes until the sauce has thickened to the texture of condensed tomato soup and coats the back of the spoon.
Recipe Note
We brighten the chile flavor with tomatoes and, because the soaking liquid for rehydrating the chiles hangs onto bitter flavor compounds, we instead blend in stock or broth to add savoriness.
