Wash the strawberries and remove the green leaves. Pluck the peppermint leaves from the stem, wash and dry a little with kitchen roll paper.
Now puree the strawberries with the leaves and transfer to a saucepan. Bring the strawberry mixture with the preserving sugar to the boil and cook for about 4 minutes. Then pour into the jam jars, which should be rinsed out again with hot water beforehand.
Turn the glasses upside down for 10 minutes, after which they can be turned over.