The champagne rounds out the strong flavors of the tequila and lime, adding bubbles and a wonderful flavor that will have you reaching for flute after flute.
(You can double or triple this recipe to make it for a crowd.)
Finely grated zest (colored part only) from one lime
1 cup fresh lime juice
1 cup Cointreau
1 cup 100% agave silver tequila
Superfine sugar, if needed for adding sweetness
Half a lime for moistening the glass rims
Coarse (kosher) salt
1 bottle chilled Brut Champagne
1. Make the margarita mixture: In a pitcher, combine the lime zest, lime juice, Cointreau, and tequila. Taste the mixture. If you like the flavor (it will be quite tart), leave the mixture as is; if it's too tart for you, stir in a little superfine sugar. Cover and refrigerate until chilled , about 1 hour.
2. Serve: Strain the mixture to remove the zest. Moisten the rims of eight 6-ounce Champagne glasses with the cut side of the lime half. Spread coarse salt on a small plate, then upend the glasses into the salt to crust the rims. Fill each glass halfway with the margarita (it'll take a generous 1/2 cup). Slowly fill the rest of the way with Champagne and hand to one of your lucky guests!