Stir together flour, baking powder and salt: set aside. In a large bowl of mixer cream butter and sugar until light. Beat in egg and peel until fluffy. At low speed or with rubber scraper stir in flour mixture until dough is smooth. Stir in zucchini and walnuts. Drop by rounded teaspoons on greased cookie sheets. Bake in preheated 190ºC F oven 15 to 20 minutes or until very lightly browned. While still warm drizzle with Lemon Frosting. Cool on rack. Makes 72 to 84 cookies. For frosting mix the two ingredients together. ----