1. Using a needle or a toothpick, prick small holes in kumquats all around; set aside.

2. Bring sugar and 2 cups water to a boil over medium-high heat. Cook, stirring, until sugar dissolves. Reduce heat to simmer and add kumquats; let simmer for 2 hours.

3. Remove from heat and let stand until cooled to room temperature. Place kumquats and liquid in an airtight container; refrigerate overnight.