Halve the lemons and limes and cut away the peel all around. Now cut out the pulp. Collect the juice and put everything together in a saucepan.
Peel the banana, mash it with the pulp of the vanilla pod and add the washed mint sprigs to the saucepan. Let everything stand for about 50 minutes.
Add the preserving sugar, bring to the boil and then cook for another 4 minutes. Now remove the sprigs of mint. Pour the jam into jars and close tightly.