Wash your zucchini and trim the ends.
Using a sharp knife or a mandolin, slice the unpeeled zucchini very thinly.
Cut the onions into small wedges and separate the layers.
Put the zucchini and the onion into a large bowl and sprinkle with the salt and cover with water.
Leave for one hour, and then drain.
Combine vinegar, Erythritol, and spices in a large saucepan and bring to the boil.
Take saucepan off the heat.
Place the drained zucchini mix into the vinegar and leave to soak for one hour.
Return pan to the heart and bring to the boil.
Reduce heat and simmer for three minutes.
Spoon into sterilised jars, top off with the vinegar blend and cap tightly.
Once opened, store in the refrigerator for up to 2 months.