Tangerine Biscotti

Stir together all-purpose flour, whole wheat flour, baking powder, and tangerine peel in a medium mixing bowl. Set aside. Beat butter in a large mixing bowl with an electric mixer on medium speed for 30 seconds. Add sugar; beat until combined. Add egg substitute and vanilla; beat well. Stir in flour mixture.

Preheat oven to 375 degrees F. Shape dough into two 12-inch-long logs. Place logs on a cookie sheet; flatten logs slightly until about 1-3/4 inches wide.

Bake for 15 to 20 minutes or until lightly browned. Cool completely on cookie sheet (about 1 hour).

Reheat oven to 325 degrees F. Cut each log diagonally into 1/2-inch-thick slices. Arrange the slices, cut sides down, on the cookie sheet. Bake for 10 minutes. Turn over. Bake for 10 to 12 minutes more or until crisp and light brown. Transfer to wire racks and cool completely.