Heat the oven to 180C/160C fan. Carefully wash the beetroot then wrap in foil and bake for 1hr until tender. Set aside to cool then peel off the skins. If the beetroot are small enough put them whole into sterilised Kilner® Jars, otherwise slice or quarter them before packing into the jars.
Put the vinegar, salt, pepper and juniper into a jug and stir until the salt dissolves.
Pour over the beetroot until they are completely covered.
Seal and leave to mature for a week before serving.