Preheat the oven to 325 degrees. Lightly grease a 9x13 pan with butter, or line with parchment paper. Sift together the flours, baking powder, and salt.
Cream together the butter and the sugar. Add the egg and the vanilla extract and mix until light and fluffy. Slowly add the flour mixture to the butter mixture, mix until combined. Add the pecans and stir again to distribute.
Press the dough into the bottom of the greased pan. Press with your fingers or a pastry roller to smooth the top of the dough.
Sprinkle the top of the dough generously with cinnamon sugar and then with chopped pecans and very lightly press them into the top of the dough.
Bake for 16-18 minutes, or until just barely beginning to brown around the edges.
Let the bars cool in the pan for 15 minutes and then cut into bars. If they are too soft to cut, let them cool for a few more minutes.
Remove them carefully to a wire rack to cool completely before storing in an airtight container. Enjoy!
Notes
Baking the shortbread in a pan and then slicing it into bars, makes this a very easy dessert. This recipe doubles perfectly and fills a large baking sheet, or jellyroll pan. Placing a sheet of parchment on top of the dough will make it easier to press/roll the dough and spread it across the pan. Remove the parchment from on top of the bars before sprinkling with cinnamon and pecans.