Pecan sable cookies

Ingredients

• 2/3 cup plus 2 tablespoons confectioners sugar
• 1-1/4 cup AP flour
• 1/2 teaspoon salt
• 1/4 teaspoon baking powder
• 1 stick or 1/2 cup or 1/4lb unsalted butter, softened
• 1/2 teaspoon vanilla extract
• 1 large egg seperated