Ruby’s Tortilleria is a small hut in the corner of a large gravel parking lot on Camino del Pueblo in Bernalillo. Residing inside that building is a feeling you’ll find in small towns up and down the Rio Grande. You’re in the heart of New Mexico but completely south of the border in spirit. If the phone cards, paletas and corrido CDs don’t give it away, the green tomatillo salsa should. On weekends Ruby’s turns the dining service up a notch, serving tamales, menudo and Mexican barbacoa. There are many faces of barbacoa. The kind that’s most commonly served at taco joints and other eateries that deal in Mexican carne is made from tough cuts of beef steamed to the point where the soft flesh can be teased apart with a spoon. The cartilage and connective tissue that give meat its toughness eventually melt into a rich, viscous, fat-like substance that makes barbacoa seem greasier than it actually is. The man at Ruby’s says his is made from beef leg. Barbacoa was originally a Taíno word, in the Arawak language group with Caribbean roots. It is believed to have meant “wooden grill"—perhaps made from wood of the bearded fig tree, after which Barbados is named. In Texas, barbacoa morphed into barbecue, as well as the barbacoa de cabeza of Tex-Mex: pit-roasted cow head that can include cheeks, neck, lips, tongue, the fatty reserves behind the eyeballs and other choice morsels. There’s also barbacoa de borrego, which means slow cooked mutton.Ruby’s barbacoa appears to be of the steamed variety, though it could be braised. Though spiced simply, it’s also rich, soft and full of complexity. For 10 bucks you get a pound of meat plus an assortment of salsas, chopped onions and cilantro, grated cabbage, and lime wedges. Pints of red and tomatillo green are sold in tied-off baggies for $1.25 each. The order comes with a stack of fresh corn tortillas, but consider buying a kilo more for $2.25. With the proper reinforcements, that pound of meat will multiply into a lot of juicy tacos.