*To toast walnuts, sprinkle in ungreased heavy skillet. Cook over medium heat 5 to 7 minutes, stirring frequently until walnuts begin to brown, then stirring constantly until light brown.
To grate the fresh lemon peel, use a Microplane® grater (similar to an old-fashioned wood rasp). It grates the peel evenly but avoids scraping the underlying pith.
For added flavor, substitute flavored yogurt, such as orange or lemon, for the plain.