Measure the oil into a large 10 inch skillet and set over medium heat.

Roll the arbol chiles between your fingers to loosen the seeds, then break them in half and shake out as many seeds as will come out easily.

Lay the chiles in the hot oil. Turn constantly until they’re aromatic and have changed color slightly, about 30 seconds.

With a slotted spoon, scoop the chiles into a blender jar, leaving behind as much oil as possible.

With a paper towel, wipe out the oil from the skillet (no need to wash). Set the skillet over medium heat and lay in the garlic and tomatillos (cut side down).

When the tomatillos are well browned, 3 or 4 minutes turn everything over and brown the other side. Scoop into the blender jar and add ½ cup water.

Blend until smooth. Pour into a salsa dish and cool.