Wash and stem the elderberries. Place them in a saucepan with a very small amount of water, cinnamon stick and lemon peel. Boil until berries burst, about 10 minutes.
Strain the mixture to get rid of seeds and return the liquid to the saucepan. Add the sugar and bring to the boil, stirring. Boil until the jam thickens.
Pour into sterilised jars and place the lids on tightly.