Wash, halve, stone and puree the plums.
Bring the jam sugar, plums and spices to the boil in a saucepan according to the package instructions, stirring continuously. Cook for about 3 minutes while stirring constantly at high heat until bubbly. Immediately pour into clean, tightly sealed jars.
Put it on the lid for about 5 minutes, then turn it over again and let it cool down.