The reserved poaching syrup is used for brushing the cake layers in the Seville Orange Chocolate Cake.
Rinse kumquats; place in a large saucepan with enough cold water to cover. Bring to a boil over medium-high heat; drain immediately. Repeat two more times, always starting with cold water.
Place kumquats, sugar, and the water in a medium saucepan; bring to a boil. Boil for 2 minutes until sugar is completely dissolved. Immediately remove from heat; let kumquats cool completely in syrup.
The candied kumquats can be used immediately or stored, refrigerated, in the syrup in an airtight plastic container for up to a month.