Source: Old Town Tortilla Factory, Scottsdale, Arizona - Arizona Republic, April 16, 2003

Bartender Rich McPherson said a citrus sweet-and-sour syrup sets the restaurants margaritas apart. It's made with equal parts sugar, water, lemon and lime juices. The Treasure Margarita is named after El Tesoro reposado tequila. (Tesoro means treasure.)

Ice
1 1/2 ounces El Tesoro reposado tequila
3/4 ounce Grand Marnier
Citrus sweet-and-sour syrup
Lime slice for garnish

Fill glass with ice. Add tequila and Grand Marnier. Fill glass with sweet-and-sour syrup. Garnish with lime slices. Makes 1 drink.

To make citrus sweet-and-sour mix: Combine equal parts granulated sugar and water and heat to boiling. Cool, then add equal parts lemon and lime juices.