I love pickles of all sorts! Pickled onions are one of my favourites, and red onion pickles are so simple to make and very versatile in recipes.
Above are the ingredients I use. I prefer to make small batches at a time. It is easy to double the recipe if you'd like to make a larger amount.
After peeling and slicing the onions, stuff them quite tightly into a glass jar of your choice. When pickling I don't like to leave much room in the jar because then the onions will be completely covered in the pickling liquid. Slice the onion anyway you prefer, in rounds are strips. This time I sliced them thicker than I usually do, they were good, but I think that thin slices are best.
In a saucepan bring the vinegar, water, salt and sugar to a boil. Give it a stir, and when the sugar has dissolved and the liquid has boiled, then pour the liquid over the onions. Close with a lid and let sit overnight for best results.
I like them on burgers as above, or on a salad, wrap or sandwich. You can try different vinegars if you like. I have made them with plain white vinegar. They turned out a little more sour than with the apple cider vinegar.
Do you make pickled red onions? What recipe do you use?
Note: These are my personal experiences and opinions. Always seek out a medical opinion for medical concerns.