Don't let the whirring of the milkshake machine worry you, there was no miscommunication: Salvador Esparza got your order right. You're not getting some slushy kiddie drink. Lily's Special Margarita on the rocks is on its way — hand delivered by Esparza himself. Lily's Mexican Restaurant sits quietly on the corner of Kingshighway and Devonshire Avenue, serving delicious Mexican food and the city's best margaritas, including the Special, which includes brandy, tequila and your choice of amaretto, Grand Marnier or Kahlúa. Any of 'em can be ordered small (12 ounces) or large (24 ounces). Rest assured, the small packs sufficient punch to kick your happy hour into high gear. Mr. Esparza whips up each margarita at the restaurant's small "bar" in the corner of the dining room, the better to delight in as you watch your ingredients get poured into a shaker, whirled in the milkshake maker and brought to your table. Don't let that pretty froth on top distract you; beyond that milkshake machine-induced layer lies a refreshingly potent cocktail just waiting to be imbibed.