Rinse the beetroots and boil them for 40–50 minutes until tender. Meanwhile, boil the brine with all the ingredients except the horseradish for about 20 minutes. Now place the beetroots in cold water, rub off the skin and ends, and slice them into pieces about 1 cm thick. Place the beetroots in sterilised preserving jars rinsed with Atamon.
Pour the boiling brine with the spices over them. You should pour right up to the rim of the jar, as the beetroots will absorb some of the liquid once they have stood for a while. Place the horseradish slices on top and seal the jar.
Store the jar in the fridge. It will keep for 4–5 months, after which the beetroots will slowly start to turn brown.
