Scrub each beet and wrap loosely in foil, then bake in the oven at 400°F for about half an hour or until tender.

Once the beets are cool, you should be able to rub off the skin with a paper towel.

Peel and slice the peeled beets.

Put the vinegar, sugar, water, mustard, and salt in a pan, and bring to a boil.

Let the mixture cool for a few minutes.

Put the beet slices and peppercorns in a clean 1-quart sized glass jar (or a pair of ½-quart ones).

Pour in the brine to cover the beets completely.

Put the lid on the jar, ensuring it’s screwed on tight.

Leave it at room temperature for 24 hours and then transfer into the fridge.