Step 1

Bring a couple cups water to a boil.

Step 2

Meanwhile, add salt, sugar and vinegar to sealable glass container and stir or shake until combined.

Step 3

Place sliced onions in medium bowl. Pour hot water to cover and let sit 30 seconds to 1 minute. Drain and add to vinegar combination.

Step 4

Place lid on container and refrigerate at least 30 minutes, up to 2 weeks.