Wash the kumquats thoroughly and remove any stems or blemishes.
Boil water in a pot and add the washed kumquats to boil for two minutes.
Drain the boiling water.
Cut kumquats in half and seperate the flesh and rind. Remove calyx and all the seeds too.
Slice and finely chop the rinds and flesh.
Place all ingredients in a large pot and leave them for 20-30 minutes.
Place the pot over high heat to bring the mixture to boil. Remove the scum carefully in order to have a clear-colored jam
Reduce heat to medium-low and simmer, stirring occasionally with a spatula to prevent burning for about 10 minutes. The marmalade is ready when it reaches a temperature of 220°F (105°C) on a candy thermometer, or when a small amount placed on a cold plate wrinkles when pushed with your finger. *1