By FOX19 Digital Media Staff| June 28, 2013 at 12:17 PM EST - Updated June 30 at 1:25 PM
1/2 cup apple cider vinegar
1 tablespoon sugar
1 1/2 teaspoon sea salt
1 red onion, sliced thin
Whisk vinegar, sugar, and salt into a small bowl. Place sliced onions into a mason jar. Pour vinegar mixture over the onions. Allow to sit at room temperature for 1 hour. Refrigerate for up to 2 weeks.