Taste the incredible deep chile flavor—the enchilada difference. Make ahead and freeze and you’ll be a happy red enchilada sauce camper. Soaking time, 30 minutes; actual working time, less than 15. All you need is a skillet, a blender and a strainer.
Warm the chiles on a comal or griddle, or in a dry cast iron skillet. You want the chiles to soften—do not allow them to burn.
Cut off the stems. (Scissors work well.) Cut a slit in the chiles and tap them over a bowl so the majority of the seeds fall out. Discard the seeds.
Place the chiles in a bowl and cover with the boiling water. Place a small plate on top to keep them submerged. Set aside for 30 minutes, or longer. (see note)
Drain the chiles, reserving the soaking water.
Place the chiles in the blender. Add the onion, garlic, salt, and if using, oregano and cumin. Pour in 1 1/4 cups of the soaking liquid. Blend until you have a smooth puree.
Strain through a wire sieve, pushing through as much of the smooth puree you can. You should have only about 2 tablespoons of skin/seeds left in the strainer.
Heat the oil in a medium skillet. Add the strained puree and cook 3 to 4 minutes, stirring occasionally. The sauce should be the thickness of heavy cream. If it seems too thick, stir in a little more of the soaking liquid.
I soaked the chiles overnight with dandy—no problema—results.