Preheat the oven to 350℉. Spray a 9x9-inch pan with nonstick spray.
In a medium bowl, whisk together the flour and baking powder.
In a large bowl, whisk together the brown sugar, melted butter and maple extract. Whisk in the eggs, one at a time, Then stir in the dry ingredients and pecans. Spread the batter into the prepared pan.
Bake for 25 to 30 minutes or until a toothpick inserted into the center comes out clean. Let them cool completely at room temperature. Cut into 16 bars. Dust with powdered sugar.