Preheat oven to 200°C (400°F). Wash the beetroots thoroughly. Trim off the leaves, but leave about an inch of stem attached to prevent bleeding.
Wrap each beetroot individually in aluminum foil and place on a baking sheet. Roast for 45-60 minutes, or until tender when pierced with a fork.
Once cooled slightly, peel the beetroots (the skin should slip off easily). Cut them into bite-sized cubes or slices.
In a saucepan, combine white vinegar, water, sugar, and salt. Bring to a simmer over medium heat, stirring until sugar and salt are dissolved.
Add the peppercorns and bay leaf to the pickling liquid. Remove from heat.
Pack the prepared beetroot into clean, sterilized jars. Pour the hot pickling liquid over the beetroot, ensuring they are fully submerged. Leave about half an inch of headspace.
Seal the jars tightly and let them cool completely. Refrigerate for at least 24 hours before serving to allow the flavors to meld.
Notes
Pickled beetroot will keep in the refrigerator for up to 2-3 weeks.