Slice up the onions. I peeled and halved each onion, then cut them into thin strips.

In a pan gently heat the vinegar, and add the salt and sugar. Stir until it has been dissolved completely, then turn off the heat. You don't want to boil the vinegar. You can add any other flavourings at this stage, I like to add a handful of black peppercorns.

Place all the onions in a colander, boil the kettle and pour all over the sliced onions.

Make sure your container is clean and sterilised. I use a Mason jar, with a wide mouth.

Once your onions have cooled down, transfer them carefully to the jar, and pour in the vinegar mixture. Depending on the shape of the jar, if the onions aren't fully submerged add in a little more, to make sure none are floating above the pickle juice.

Once the jar is cooled down, I store them in the fridge. You can enjoy them the next day, but I think they taste best after a couple of days pickling when they have turned bright pink. The first picture is just after filling the jar. The second one is after a few days pickling, and put on some cheese and biscuits.