Place peaches, water and sugar in a pot over medium heat. Bring to a boil and let cook for 5 minutes until peaches are macerated. Reduce to low and let simmer until liquid is reduced by half (12 minutes or so).
Remove from heat and let cool. Once cool, strain through a fine mesh sieve. (Note: reserve the peaches if you’d like. They’re like candy at this point. I may or may not have put them on vanilla ice cream when they were still warm. Good life decision.)
Pour simple syrup into the bottom of a glass.
Add gin and superfine sugar and mix.
Top with club soda and garnish with a floating peach slice and a few blueberries.