• Combine the lime zest and coarse sugar in a shallow bowl with the tines of a fork. On a very small, shallow saucer, pour a tablespoon or two of the simple syrup. Dip the rims of two cocktail coupes into the shallow pool of simple syrup and then immediately dip into the lime sugar. Set inside the refrigerator to set up.
• Add the apricots to a glass shaker along with the Bourbon and using a muddler, work the mixture into a mash so the apricots are juiced and combined with the Bourbon VERY WELL. Place into refrigerator to chill, about 2 to 3 hours.
• Once Bourbon apricot mash has chilled, add the lime juice, simple syrup and elderflower liqueur. Muddle once more. Add ice to the glass shaker and fit with a top. Shake vigorously and strain into the prepared sugar-rimmed coupes.
• Fill remaining room in coupes with the club soda or a well-chilled sparkling wine.
• Garnish with a single stem of fresh thyme.

An optional additional step; once the apricot mash has been strained, the remaining fruit and fruit pulp may be gently pulsed with fresh thyme leaves and then spooned into and frozen in ice cube trays. Add the 'cubes' to the cocktails when ready to serve.