I have refined the art of making pickled onions over a number of years of trial and error. Strictly speaking, these are shallots
but make for a tasty alternative nonetheless.
Peel the onions and shake salt over them so that each onion is in contact with salt. Cover the bowl with cling film and leave them to salt for 24 hours. This draws out some of the moisture from the onions. I find that when you pickle them in vinegar, the vinegar is drawn back into the onion to replace the lost water which preserves it. This makes for a really crunchy onion which is never soft.
Quickly rinse the onion under some water and leave on a tea towel to drain and dry completely. Pack the onions into warmed sterilized jars and decorate with a bayleaf and dried chilli if you like. These were some of my Bishop's Kiss chillis from last year!
Now this is the key to the whole recipe.. the vinegar. I use a proportion of 3 parts malt vinegar to 1 part water. There is nothing nastier than pickled onions made with plain vinegar, they are horrid! So if you are using one pint of vinegar, add one ounce of sugar. This will NOT make the onions sweet in any way, it brings out the flavour and stops the vinegar being too acidic to taste. Add some pickling spice to this and just bring it to the boil. Allow the spices to steep for a few minutes and take off the boil.
Very slowly (so as not to crack the glass) pour the hot, spiced vinegar over the onions right to the top of the jar. I leave some of the pickling spice in the jar for flavour but you can drain it out if you want. Wiggle the jars to allow any bubbles to rise and seal the jars immediately while it is still hot. When it cools the hot air will shrink in size and create a vacuum seal. They should be ready to eat in a month or so.
This process was thoroughly supervised by my lovely kitchen assistant!