Mariano's has been known for decades as the creator of the frozen margarita, but their more impressive accomplishment is what they've done with fajitas. If fajitas were measured by their sizzle, Mariano's would win based on heat alone, but there's a lot more to celebrate here beyond a hot metal plate. The beef is perfect — a little chewy, a little salty, with a big, smoky flavor that goes perfectly with the sweetness of the caramelized onions that share the plate. What's better is all of these flavors get wrapped up in tortillas that were patted out and griddled moments before at the station at the front of the restaurant.