Rinse the plums and cut them in halfs and remove the stones
Grate the peel of the lemon and squeeze the juice of the lemon
Combine the plums, lemon zest, lemon juice, lavender flower, and sugar in a pot and turn up the heat on the hob
Let the jam cook for 20 minutes without a lid (taste once in a while and remove the lavender if/when you like the taste)
Allow the jam to cool (remember to remove the lavender) and pour the jam into a glass