Mi Cocina These folks are pushing the national frozen drink of Texas to dizzying new heights. The frozen mango margarita is quite good, with lots of rich tropical-fruit flavor and not too much sugar. The "mambo taxi," made by alternating layers of frozen margarita and sangria, is excellent as well. But it's the three-tone margarita parfait, the "dilemma," that is truly a towering achievement. Served in a tall pilsner glass, this tequila monster has alternating layers of mango, strawberry and pale green lime frozen margarita slush. It's served straight from the freezer, and, like a liquid-nitrogen-fueled rocket just before liftoff, sheets of ice form on the cocktail's cylindrical exterior. It's pricey at ten bucks, but the "dilemma" packs more wallop than any two conventional margaritas, and the variety can't be beat: All you have to do is maneuver the straw to change flavors.