1. Peel the onions and place them in a bowl with the
water and two teaspoons of salt (see note).
2. Leave them covered overnight.
3. Put two medium-sized glass jars and their lids (the
lids being separate from the jars) in a pan of water and heat gently until
the water is boiling. Boil gently for 5 minutes. Take the jars out of the
pan, and stand them upside down on a tea towel. This procedure sterilises
4. Drain the onions and put them in the sterilised jars.
5. Measure out the vinegar and stir in the mustard,
sugar, salt and pepper. Continue to stir until the sugar has dissolved.
6. Pour the vinegar mixture over the onions, filling
both jars. Leave a quarter inch gap at the top. If you don’t have quite
enough mixture you can top it up with a little extra cider vinegar.
7. Screw the lids on tightly and shake the jars well. Keep
in the refrigerator for a month;: they will benefit from being shaken
every few days.