Cut the lemon into slices, simmer together with the blossoms and the sugar in 1 liter of water for half an hour. Let cool and strain. Express the flowers well.
Stir the preserving sugar into the syrup and cook according to the instructions on the packet.
After a successful gelling test, pour into small jars and close immediately.
Tastes great on breakfast rolls, but also to flavor game or to sweeten tea.