Peel and chop the beets.

Place them in a saucepan with the water and onion. Bring to a boil and simmer about half an hour. Chill.

If desired, use an immersion blender to chop the vegetables more finely - but leave them with texture, do not puree. Add sour salt or lemon juice to taste - you want it tangy, but not unpleasantly sharp.

Serve ice cold, with a dollop of sour cream in each bowl. If you want a heartier soup, potato or egg are also traditional additions.