3 med. baking potatoes (about 2 lbs.)
4 1/2 c. chicken broth
1 1/2 c. watercress leaves, firmly packed
6 green onions with tops, coarsely chopped (about 3/4 c.)
1/3 c. fresh dill, chopped
2 sm. hothouse or European cucumbers, peeled, or 3 regular cucumbers, peeled & seeded (about 2 1/4 pound)
1 tsp. sugar, or to taste
3/4 tsp. salt, or to taste
1/2 c. plain yogurt
Plain yogurt and fresh chopped dill for garnish

Peel and chop the potatoes into 1/2 inch pieces. In a deep saucepan, bring chicken broth, potatoes and watercress to a boil. Reduce heat and simmer, partially covered, over moderate heat until soft, 15 to 20 minutes. Meanwhile, in a food processor fitted with the metal blade, chop green onions and dill until minced. Coarsely chop cucumber, add to processor and process until pureed. Scrape down sides and process until smooth, about 1 minute. Transfer to a large nonaluminum bowl. When potatoes are tender, use a slotted spoon to transfer them and watercress to same food processor work bowl. Add 1/2 cup of the broth and process until smooth. Remove to bowl with cucumber; stir in remaining broth, seasonings and yogurt. Refrigerated until chilled. Serve chilled, garnishing each serving with a dollop of yogurt and a sprinkling of chopped dill.

Serves 8.