Okroshka (Cold Kefir Soup)

Okroshka is traditionally made with kvass, a fermented rye drink that's hard to find outside of Eastern Europe. In this version, kefir, a yogurt-like beverage, provides that fermented tang. The mix of fresh herbs, radishes and cucumber keeps the soup refreshing, while the boiled eggs and potatoes give it enough heft for a light main dish. Kefir can generally be found in the dairy section of health food stores (if you can't find it, you can substitute a slightly lesser amount of yogurt).

Makes 6 servings, as a first course

3 cups plain kefir

1 1/2 cups water

1/4 cup finely chopped scallions

1/4 cup finely chopped dill

1 small bunch radishes, cut in half and thinly sliced

1 small cucumber, peeled and cut into 1/4-inch dice

4 hard-boiled large eggs, cut into 1/4-inch dice

2 midsize boiled waxy potatoes, cut into 1/4-inch dice

Salt and pepper to taste

Mix together all of the ingredients and chill. Serve cold.