Preheat oven to 400°F.

Wrap each beet tightly in aluminum foil and place on the middle oven rack. Roast for one hour or until easily pierces with a fork.

When beets are cool enough to handle, peel off the skins and discard.

Cut the beets in to 1-in chunks and place in food processor. Add the vinegar, salt and 1 cup of the yogurt. Puree until smooth.

To serve, divide the remaining yogurt another the bowls and top each with some beet puree. If desired, swirl together with a spoon.