The word "faja" is Spanish for belt or girdle and "fajita" is the diminutive form. In original Tex-Mex culinary parlance, fajitas are a dish with roots in the Rio Grande Valley made from a specific cut of meat: skirt steak. Considering the appearance of the meat a strip about 18 inches long and about one inch thick and its placement in the beef carcass beneath the heart and lungs, fajita (little belt) is a particularly apt nickname. There are only four skirts per beef carcass, yielding about 8 lbs. of meat. The two outside skirts are the diaphragm muscle from the forequarter and the two inside skirts are the secondary flank muscle from the hindquarter. For many years, butchers included the skirts in the "table trimmings" ground up for hamburger. Inside skirts are more likely to be tough and need meat tenderizer or a marinade of some kind of acidic liquid such as lime juice, beer, or salad dressing. For the utmost tenderness and palatability, Sonny Falcon swears by unseasoned, unmarinated outside skirts. He insists on a hot fire and instructs that butterflied pieces of meat should be turned regularly for six to eight minutes. "If they stay on one side long enough to get grill marks, you're not turning them often enough," says the master. Once the meat is done, cut thin slices
against the grain
, wrap a few slices in a warm flour tortilla, and serve with salt and hot sauce on the table. That's the genuine article, a real fajita. Everything else is tacos al carbon, chicken girdles, and shrimp belts.