5 steps, about 15 minutes start to finish.
Peel the red onion and slice it thinly.
Place the sliced onion in a mason jar or another glass container with a tight-fitting lid.
In a small saucepan, combine the apple cider vinegar, sugar, and salt. Heat the mixture over medium heat, stirring occasionally, until the sugar and salt dissolve.
Pour the vinegar mixture over the sliced onion in the jar, making sure that the onions are fully covered with the liquid.
Cover the jar with the lid and refrigerate for at least 30 minutes before using. The longer you leave the onions in the pickling liquid, the more flavorful they will become.
“Warm the vinegar just until the sugar and salt dissolve, then pour it over the onions while it's still hot so they soften and take on color. They're good after 30 minutes but even better the next day.”
