This is a great basic sauce that can accompany enchiladas, be spooned over tamales, or be used as a dip for chips.
4 dried New Mexican chiles, stems and seeds removed
6 dried arbol chiles, stems and seeds removed
2 medium Roma tomatoes, cored
1 medium yellow onion, peeled and quartered
1/2 cup cilantro leaves and tender stems
2 medium cloves garlic, peeled
2 teaspoons dried oregano
1 teaspoon ground cumin
Combine chiles and tomatoes in a small saucepan, cover with water, and bring to a boil over medium-high heat. Cook until chiles and tomatoes have softened, about 5 minutes.
With tongs or a slotted spoon, remove chiles and tomatoes from water and place in a blender along with remaining ingredients. Pour in 1 1/4 cups of the chile cooking liquid. (You may have to do this in batches to avoid overflowing.) Cover and blend on high until smooth, about 4 minutes.
Season well with salt and serve immediately, or cover and refrigerate for up to a week.