Yield 1
Put bourbon, vermouth, syrup and one kumquat in a shaker and muddle. Add ice. Stir to chill and dilute. Strain into glass and garnish with the remain kumquat. Add a few drops of either orange of even better, cardamom bitters.
Recipe by Elizabeth Minchilli at https://www.elizabethminchilli.com/2022/01/kumquat-old-fashioned/