In glass muddle together sugar and kumquats until almost syrupy.
Pour in gin and St. Germain and a splash of the club soda, muddle the kumquats a bit more.
Put ice in cocktail shaker and pour in gin mixture. Shake it up and pour into tumbler. Make sure the ice goes to the top, if it doesn't, add more. A good cocktail is full of ice.
Pour in drink and garnish with rosemary sprig
Drink!
Recipe by Talia Bunting at https://www.taliabunting.com/st-germain-kumquat-cocktail/