Yield: 1 quart
½ cup apple cider vinegar
1 cup warm water
1 tablespoon brown sugar
1½ teaspoons kosher salt
Pinch of red pepper flakes
1 medium red onion, thinly sliced
Combine vinegar, water, brown sugar, salt and pepper flakes in a medium bowl. Whisk together until sugar and salt are fully dissolved.
Place onion slices into a jar or bowl and pour vinegar mixture over until full. Let sit at room temperature for 1 hour, then cover jar or bowl and place in refrigerator for 24 hours. Store, covered, in the refrigerator for up to 1 week.
—Recipe developed for Edible Omaha by Julie Kolpin