Preheat oven to 350°F Combine first 5 ingredients in a large bowl. Combine vanilla with next 2 ingredients. Add to flour mixture; stir until well blended (dough will be dry).
Turn dough out onto a lightly floured surface and knead lightly 7 or 8 times. Shape dough into a 16-inch-long roll. Place roll on a baking sheet coated with cooking spray; flatten to 1-inch thickness.
Bake for 30 minutes. Let cool. Cut roll diagonally into 24 (1/2-inch) slices, and place slices, cut sides down, on baking sheet. Reduce oven temperature to 325F and bake for 10 minutes. Turn cookies over and bake for an additional 10 minutes (the cookies will be slightly soft in center but will harden as they cool). Remove from baking sheet, and let cool completely on wire rack.