Prepare the pan and pre-heat. Adjust oven rack to middle position; heat oven to 350° F. Line a 13 by 9-inch baking pan with foil, leaving enough overhang to help you lift the blondies from the pan when they're done. Turn the pan upside down, and form the foil over the bottom to make the shape of the pan with the foil. Turn the pan back over and press the pre-shaped foil in the bottom. Spray with cooking spray and set aside.
Combine the dry ingredients. Whisk flour, baking powder, and salt together in medium bowl; set aside.
Combine the wet ingredients. Melt the butter over medium heat and allow to cool slightly. Whisk in to the butter, the brown sugar together until combined. Add eggs and extracts and mix well.
Combine the wet and dry ingredients. Pour the wet ingredients into the dry ingredients and whisk together until smooth. Be sure to not overmix. Stop whisking once the flour has just been incorporated.
Fold in the raspberries and white chocolate chips. Using a rubber spatula, fold in the raspberries and white chocolate chips being careful to not smash the raspberries too much. If you use frozen berries, do not thaw before adding them to the bowl.
Bake and cool your bars. until top is shiny, cracked, and light golden brown, 30 to 35 minutes; do not overbake. Cool on wire rack to room temperature. Remove bars from pan by lifting foil overhang and transfer to cutting board. Cut into 12 large or 16 small(ish) bars and serve.