First things first. Scrub the beets clean under running water. Trim off the tops and roots. Place them in a large pot and add enough water to cover them. Bring to a boil, then simmer until they’re tender when poked with a fork—about 45 minutes.

While the beets are cooking, prep your brine. In another pot, combine water, apple cider vinegar, sugar, and sea salt. Toss in the cinnamon sticks, whole cloves, bay leaf, allspice berries, and mustard seeds. Bring this mixture to a boil. Once it’s boiling, reduce the heat and let it simmer for about 10 minutes to allow the flavors to meld.

Once the beets are cooked, drain and cool them under running cold water. Peel off the skins—this should be easy now. Slice the beets into thin rounds or wedges. Also, slice the onions into rings.

Pack the sliced beets and onions into sterilized jars. Pour the hot brine over the beets and onions, ensuring they’re fully submerged. Seal the jars immediately.

For those who want to ensure long-term storage, use a water bath canning process. Place the sealed jars in boiling water for about 15 minutes. Remove them and let them cool completely.