Joe Hargrave's aha moment came in a Mexico City taqueria, when he realized the place was built around just six amazing tacos and a few great salsas. "But it was all exactly what I wanted to eat," he says. Back home, Hargrave closed his struggling Spanish eatery and, within a year, opened a simple taqueria, just like that one in Mexico, called Tacolicious, in San Francisco's Mission District. "Telmo, our chef, grew up in Portugal and in a Mexican neighborhood in San Jose," says Hargrave, "so he's steeped in the classics." His ultratraditional bistec adobado boosts grilled beef flavor with a quick sauce of vinegar, spices, and chilies. "We use flank steak," says Hargrave, "but skirt or tri tip are also good; you want a cut with some chew."

• 1 tsp cumin seeds
• 1/3 cup apple-cider vinegar
• 1/3 cup water
• 2 dried ancho chilies*, stemmed and deseeded
• 2 dried guajillo (or New Mexico) chilies, stemmed and deseeded
• 1 dried cascabel chili, stemmed and deseeded
• 2 tbsp canola oil
• 1/4 medium yellow onion, chopped
• 4 garlic cloves, peeled
• 1 tsp freshly ground black pepper
• 1 tbsp kosher salt, or to taste
• 2 lbs flank steak
• 1 big bunch green onions, root ends trimmed
• Lime wedges, chopped onions, and cilantro for serving
• 12 tortillas

*Don't be intimidated by the exotic-sounding chilies – many are available at Whole Foods or even Walmart, and all can be found at your local Mexican grocer.

Step one
Toast cumin seeds in a skillet over medium heat for 1 minute, then grind in a spice grinder (or substitute 2 tsp preground cumin and skip the toasting).

Step two
Heat vinegar and water in a pan until hot. Pour into a bowl with the ancho, guajillo, and cascabel chilies. Let stand 15 minutes.

Step three
For the adobo marinade, put 3 tbsp oil in a pan over medium heat, add onions and garlic, sauté until browned, place in a food processor. Add chilies and their soaking liquid, cumin, black pepper, and salt. Puree to a thick, smooth paste. Pour into a bowl, cover, and refrigerate.

Step four
Place beef and adobo in a large ziplock bag, massage to coat all sides. Refrigerate 2 to 12 hours, the longer the better.

Step five
Remove steak from refrigerator 1 to 2 hours before cooking. Grill over medium-high heat 5 to 7 minutes per side.

Set aside to rest covered for 10 minutes.

Step six
Rub green onions with oil, grill until soft and slightly charred, 2 minutes. Season with salt.

Step seven
Cut steak into small pieces against the grain. Season with salt and pepper, serve with green onions, cilantro, chopped onions, and lime wedges.