This recipe, courtesy of Jace and Paige Arans, can easily be multiplied to make by the batch.
3 ounces Don Julio Tequila, Reposado or Anejo
4 ounces Topo Chico Mineral Water
juice of 1 lime
several dashes of orange bitters
agave nectar, to taste (optional)
lime slices, for garnish
Mix all ingredients in a highball glass until well combined. Add ice to fill glass and garnish with lime slices. Makes 1