-the wafer:
1/2 ts Baking powder
6 tb Unsalted butter
1/2 c  Pistachios; finely chop
2/3 c  Granulated sugar
-chocolate glaze:
1    Egg yolk
4 oz Semisweet chocolate
1/2 ts Vanilla extract
2 ts Vegetable oil
1 c  All-purpose flour
1/4 c  Pistachios; finely chop

1. In a food processor or with an electric mixer, cream together the
butter and sugar. Add egg yolk and vanilla and mix till smooth. Add flour
and baking powder, stirring baking powder in slightly to distribute it, and
pulse or beat until flour is incorporated. Stir nuts in by hand. Turn out
onto 2 sheets of plastic wrap and form two 6″ logs. Wrap well and
refrigerate for at least 2 hours or up to 3 days. Dough can be frozen for
one month. 2. Preheat oven to 350~F. Using a sharp knife, cut chilled dough
into rounds 1/4″ thick. Arrange 1-inch apart on ungreased cookie sheets,
reshaping into rounds if needed. Bake 10-12 minutes, until edges are
lightly browned and cookies are pale golden. Cool on a rack. 3. To make
glaze, melt chocolate with oil. Dip with one half of each cookie. Roll
glazed edges in chopped pistachios. Let stand for 2 hours or until glaze
has set. Store covered for 2 days at room temperature or freeze for 2
weeks.