Put at least 3 cups of water on to boil.

Slice your onion and place in a strainer. I cut the onion in half, then sliced the rings, but you can do full rings or even chopped onion if you'd prefer to use them that way.

Combine the vinegar, sugar, and salt in the 2 cup jar that you'll be using for the pickles. Cover and shake to dissolve.

When the water has come to boil, pour 1/2 a cup and reserve. Place the strainer with onions into a large bowl and pour the remaining hot water over the onions and let them sit for 1-2 minutes.

Add the reserved water to the brine mix and continue swirling to dissolve sugar and salt. Add optional spices.

Quickly remove the strainer from the hot water and remove excess water from the onions.

Add the onions to the brine in the jar. Cover and seal and let them pickle in refrigerator for at lease 2 hours, but overnight is better.