Step 1

Pack sliced onions into a mason jar. If using, insert a cinnamon stick and 1 star anise with the onions.

Step 2

Combine the water, apple cider vinegar, salt, and sugar. Heat in a saucepan over medium high until boiling, stirring to dissolve the sugar and salt.

Step 3

Pour the brine mixture into the jar with the onions, being sure to completely cover. Let sit at room temperature for 45 minutes.

Step 4

Serve immediately or cover and refrigerate up to 3 weeks.