Preheat the oven to 350 degrees F (175 degrees C).
In a medium bowl, stir together the flour, brown sugar, pumpkin pie spice, cloves, and baking powder. Mix in the butter using a fork until well blended. The dough will be flaky and separated. Stir in the pecans, and press into an 8 inch square pan.
Bake for 25 minutes in the preheated oven, or until lightly browned on the top. Cut into squares while still warm, but do not remove from the pan. Allow to cool, then dust with confectioners' sugar.
