Recipe by: Sue Klapper In a large mixer bowl beat butter or margarine with an electric mixer on medium speed for 30 seconds or till softened. Add sugar, cocoa, and baking powder; beat till combined. Beat in the eggs. Beat in as much of the flour as you can. By hand, stir in any remaining flour, chopped white baking bar, and semisweet chocolate. Divide dough in half. Shape each portion into a 23 cm long log. Place logs about 10 cm apart on a lightly greased cookie sheet. Flatten logs slightly till about 5 cm wide. Bake in a 375 oven for 20 to 25 minutes or till a toothpick inserted near the center comes out clean. Cool on the cookie sheet on a wire rack 1 hour. With a serrated knife, cut each log diagonally into 1 cm thick slices. Lay slices, cut side down, on an ungreased cookie sheet. Bake slices in a 325 oven for 8 minutes. Turn slices over; bake for 7 to 9 minutes more or till biscotti are dry and crisp (do not overbake). Cool thoroughly on a wire rack. Store the biscotti in an airtight container at room temperature for up to 1 week or freeze, in a freezer container, for up to 6 months. Makes about 32 slices.