Preheat oven to 350 degrees. Line an 8-inch square pan with parchment paper, leaving an overhang. Spray parchment with non-stick cooking spray.

In a medium bowl, mix flour, pecans, baking powder and salt. In large bowl, beat softened butter, granulated sugar and 1/2 cup powdered sugar with electric mixer on medium speed until fluffy. Beat in egg and vanilla.

On low speed, gradually beat flour mixture into butter mixture until well blended. Spread dough evenly into prepared pan.

Bake for about 35 minutes or until light golden brown. Remove from oven and immediately sprinkle about 2 tablespoons of powdered sugar over top. Cool completely.

Remove bars from pan by lifting parchment. Cut into 1 inch squares. Sprinkle with an additional 2 tablespoons powdered sugar. Store in airtight container at room temperature.