Simply the best margaritas. We no longer bother getting them out because they never measure up.
4 tsp lime zest
1/2 cup fresh lime juice
4 tsp lemon zest
1/2 cup fresh lemon juice
1/4 cup superfine sugar
pinch salt
2 cups crushed ice
1 cup 100% agave tequila, preferably reposado
1 cup Triple Sec
Combine zests, juices, sugar, and salt, cover, refrigerate 4 to 24 hours (or longer)
Add alcohol & half the ice, shake well to combine.
Salt the glass rims
Serve over more ice.
I often use regular granulated sugar instead of superfine, it just needs more mixing. Giving it a whir in the food processor would work too.
I generally make up the mix (using a lot of long strips of zest–easier to strain out) and then make up margaritas as desired using equal portions of mix, tequila, and triple sec.
The sour mix freezes well in ice cube trays, then turn out into a zip-top bag. Combine equal portions mix, tequila, and triple sec and shake until the sour mix melts. Then add ice and continue as per above.