Cut the onion and the garlic cloves into small cubes.
Finely chop the mint, rub off the lemon peel.
Put all ingredients in a saucepan and bring to the boil. Slowly reduce over low heat - can take up to 2 hours. Stir well, especially at the end, as the mixture can easily burn.
Pour the chutney into twist-off glasses while it is still hot and leave to cool while standing on the lid.