Extract the oils: Add 2 cups sugar to the zest and rub mixture together with your hands for 1-2 minutes until it resembles wet sand. and becomes very fragrant.

Steep the syrup: Pour 2 cups boiling water over the sugar mixture, stir to combine until sugar has dissolved, and let sit undisturbed for 15 minutes to allow flavors to fully infuse.

Strain: Pour syrup through a fine mesh sieve into a clean jar or bottle, pressing zest with the back of a spoon to extract remaining liquid before discarding solids.

Mix drinks: For each serving, add 1-2 tablespoons syrup to a glass with ice, stir in 1 tablespoon fresh lime or lemon juice, and top with sparkling water to taste.