Beat butter at medium speed of an electric mixer until creamy; gradually add powdered sugar, beating well. Gradually add flour and wheat germ, beating just until blended. Turn dough out onto wax paper (dough will be soft). Pat dough into a rectangle; cover and chill 30 minutes or until firm.
Transfer dough to a lightly floured work surface; roll to 1/4" thickness. Cut dough into 3" x 1" rectangles, using a fluted pastry wheel. Place 1" apart on ungreased cookie sheets. Sprinkle with turbinado sugar.
Bake at 325° for 19 to 20 minutes or until barely golden. Cool 5 minutes on cookie sheets. Remove to wire racks, and cool completely.
Variation: To make shortbread squares, cut dough with fluted-edge square cookie cutters.
Turbinado defined: Turbinado sugar is coarse raw sugar with delicate molasses flavor and golden color. Look for it at large supermarkets near sugar and spices on the baking aisle.
Why unbleached flour? Many gourmet cooks believe flour that hasn't been bleached has the freshest flavor and highest quality for baking. It's the flour to use in simple recipes in which you'll taste pure flavors. Unbleached and bleached all-purpose flour can be used interchangeably in baking.