In a large bowl, whisk together flour, baking powder, and salt.
In a medium bowl, whisk together brown sugar, butter, eggs, and maple extract.
Fold the wet ingredients into the dry ingredients, mixing until just combined.
Fold in the pecans and white chocolate chips, careful not to overmix. The mixture will be quite thick.
Spread into the bottom of a greased 9x13-inch baking pan.
Bake at 350 degrees for 22-25 minutes, or until edges are golden brown, the top is shiny and crackled, and a toothpick inserted near the center comes out clean.
Cool completely in pan on a wire rack. Cut into 24 bars.