Step 1

Combine water, vinegar, sugar and salt in a mixing bowl and stir until sugar dissolves.

Step 2

Pack sliced red onions into glass jars. Pour the warm brine over the red onions and allow to cool slightly with the lid off. Cover and refrigerate.

Step 3

After 1 day, the Pickled Onions will be good. After two days, the Pickled Onions will be perfect. They'll keep for up to 2 weeks after that.