Adjust oven rack to middle position; heat oven to 350° F. Line a 13 by 9-inch or 11 by 7-inch baking pan with foil, leaving enough overhang to help you lift the blondies from the pan when they're done. Spray with cooking spray and set aside.
Whisk flour, cinnamon, baking powder, and salt together in medium bowl. Make a well in the dry ingredients.
Melt the butter over medium heat and allow to cool slightly. Add the melted butter, sugars, vanilla, egg. Using rubber spatula, fold dry ingredients into egg mixture until just combined; do not overmix. Fold in Reese's candies and chocolate chips and turn batter into prepared pan, smoothing top with rubber spatula.
Fold the white chocolate chips and turn batter into prepared pan, smoothing top with rubber spatula.
In a small bowl, combine the topping ingredients and sprinkle over the batter. If making them in a 11 x 7 pan you may not use all of the topping.
Bake until top is shiny, cracked, and light golden brown, 22 to 25 minutes (for the 9 x 13 pan); 30-35 minutes for the 11 x 7 pan- 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.