1preheat oven to 350°. Spray a 13 x 9" baking pan with nonstick cooking spray.
2In large bowl mix flour, baking powder, salt, coconut and pecans. Stir to mix. Stir the Brown sugar into the melted butter. Add eggs one at a time; stir after each addition. Stir in vanilla. Pour butter mixture into the flour mixture. Stir until just combined. Spread batter into prepared pan and bake for 20 to 25 minutes or until Golden Brown.
3Immediately remove bars from oven and spread with marshmallow fluff. Drop teaspoons of dulce de Leche on top of marshmallow and swirl with a knife.
Cool completely and refrigerate until chilled; cut and serve. Makes 24 bars.