Ingredients
2 limes
1/4 cup white sugar
3 tablespoons water
1 cup premium tequila
2 tablespoons brandy-based orange liqueur (Grand Marnier®)
1 lime, sliced into rounds
coarse salt

Directions
1. Grate the zest of 2 limes into a small bowl. Cut the zested limes in half, and squeeze the juice into a measuring cup to get 1/2 cup. Combine lime zest, lime juice, sugar and water. Cover, and refrigerate for approximately 24 hours.
2. Before serving, stir in the tequila and Grand Marnier. Rub rim of 4 glasses with sliced lime, and dip into salt. Take another slice of lime, cut in half, slice under skin of lime to halfway point, and place on glass for garnish.