Step 1

Add the vinegar, water, sweetener and salt to a saucepan and heat to a simmer. Whisk until dissolved.

Step 2

Slice the ends off the onion, then slice in half vertically. Slice each half into vertical very thin slices. I used a mandolin to get very thin slices.

Step 3

Add the onion slices and peppercorns to a mason jar, then pour the pickling liquid over the top and fill up the jar.

Step 4

Add the lid on and seal with the lid. Let the onions sit at room temperature until they have cooled, about 20 minutes or so, then place them in the fridge to chill.

Step 5

Once they have cooled completely, they are ready to use.

Step 6

Store in the same jar in the fridge for up to 2 weeks.