For the buttermilk drink, wash the plums and remove the stone. Place all ingredients in a stand mixer and mix vigorously. The plums should be completely pureed. Pour the drink into glasses and serve with a straw.
Preparation Tip:
If it's not sweet enough, you can add some honey to the buttermilk drink. Or you can use a very ripe banana for a little more sweetness. Instead of cinnamon, vanilla also adds a subtle note.