Preheat oven to 350 degrees F. Grease cookie sheets.
In large bowl mix all ingredients at medium speed, except walnuts and confectioners' sugar, occasionally scraping bowl with rubber spatula.
Stir in walnuts.
Drop mixture by rounded teaspoonfuls, 1/2 inch apart, onto cookie sheets.
Bake 10 minutes. Remove cookies to wire racks; cool. Sprinkle with confectioners' sugar.