This isn't exactly diet fare, but it's surprisingly refreshing on a hot summer evening.
Cold Lemon Soup
4 cups (1 L) vegetable or chicken stock
2 cups (500 ml) heavy cream
2 Tbs (30 ml) cornstarch (cornflour) mixed with
1/4 cup (60 ml) water
6 egg yolks, beaten
1/2 cup (125 ml) lemon juice
Salt and freshly ground pepper to taste
Bring the stock and cream to a simmer in a pot over moderate heat. Stir in the cornstarch mixture and cook, stirring frequently, until slightly thickened. Stir a little of the mixture into the egg yolks, and then stir the egg yolks into the soup. Stir over low heat until thickened - do not boil. Chill in the refrigerator and stir in the lemon juice, salt, and pepper immediately before serving. Serves 4 to 6.