Measure the oil into a large (10-inch) skillet and set over medium heat. Roll the árbol chiles between your fingers to loosen the seeds, then break them in half and shake out as many seeds as will come out easily. If using guajillos, tear them open and sweep out the seeds with your fingers. 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 it). Set the skillet over medium-high heat and lay in the garlic and tomatillos (cut side down). When the tomatillos are well browned, about 4 minutes, turn everything over and brown the other side. Scoop into the blender jar and add ½ cup water. Blend until nearly smooth. Pour into a salsa dish and cool.
Thin with a little additional water if necessary to give the salsa an easily spoonable consistency. Taste and season with salt, usually about ½ teaspoon.
Riffs on Salsa Roja: Though I love the rich flavor that oil-toasting gives the chiles, dry pan-toasting (for chiles, garlic and tomatillos) is a common variation. Practically any small dried chile can be (and has been) used to make this salsa: the little round, nutty-tasting cascabels; smoky dried chipotles, moritas or moras; the very hot pequíns or tepíns; regional chiles like the onzas, catarinas, costeños—the list could go on for pages.
Spicy Baked Chicken with Mango: For even cooking, I usually choose either 8 thighs or 4 breast halves—with bone and skin in tact (for best flavor and texture). In a large bowl, toss chicken with salsa to evenly coat. Spread chicken skin-side up into a single layer in a baking pan. Bake at 400 degrees until just done through, about 20-30 minutes for the breasts, 30-40 minutes for the thighs. Scatter a large, peeled, sliced mango (or 2 peaches or nectarines) over the chicken while it's baking, to add a sweet note to all the spiciness.
Recipe from Mexican Everyday by Rick Bayless with Deann Groen Bayless.
