Build in collins glass filled with ice, stir gently, garnish with lime.
To make the aqua de tamarindo, take 8 tamarind pods, shell removed (or about 8 tablespoons of block tamarind paste) and add it and half a cup of piloncillo (Mexican brown sugar) to 1 quart of simmering water. Simmer for 1 minute, remove from the heat and pour into a bowl. Let the tamarind soak for two hours, then using your hands, rub the pods to remove the tamarind paste. Strain and bottle.