Preheat oven 350 degrees. Coat an 8x8 baking pan with butter or cooking spray. In a medium bowl, whisk brown sugar into butter, followed by eggs, vanilla and mashed banana.
In another bowl, sift flour with baking powder and salt. Add dry ingredients to creamed mixture. Add in chocolate chips and pecans, stirring until just mixed.
Pour mixture into the prepared pan and sprinkle with turbinado sugar if desired. Bake 30-35 minutes or until a knife inserted in the center comes out clean.
TIP: If you like a thicker, cakier bar, use the 8x8 pan as suggested. If you prefer a thinner, flatter bar cookie, use a larger pan, such as a 13x9 baking pan. Once cool, cut into 12 pieces.
Recipe by In Good Taste at https://ingoodtaste.kitchen/monkey-bars/