Carne Asada Tacos

Norteño cattle country — Sonora, Nuevo León, Chihuahua — late 19th century, when Mexico's northern ranches industrialized beef and the vaqueros grilled trim cuts (the chuck and skirt the patrón didn't want) over mesquite coals. The taco form took hold mid-20th century in border cities; the flour tortilla is northern, reflecting wheat agriculture introduced by Spanish colonists rather than corn.

Norteño grilled-beef tacos — Sonora and Nuevo León run skirt or arrachera over mesquite, on flour tortillas north of Monterrey, corn south. The lime-orange-soy marinade is a Tijuana adaptation; rural Sonora just salts.

Skirt or flap steak grilled hard over mesquite, chopped on the board while still hissing, piled into a small flour or corn tortilla. Lime, cilantro, raw white onion, salsa cruda — that's it. The meat should taste of smoke and beef fat, not marinade. A good one drips a little; a great one has crisp charred edges next to medium-rare interior.

Skirt steak's coarse longitudinal grain is the point — slice across it after grilling and the meat is tender; slice with the grain and it's chewy rope. The marinade question is contested: purists use only salt and lime, arguing acid-and-citrus marinades steam the surface and block char. A dry-salted skirt over real coals beats any soy-orange-cumin slurry.