First start by preheating the oven to 350F and preparing an 8x8 inch baking sheet. Spray it with cooking spray then line it with parchment paper
Now, mix all the dry ingredients (flour, baking powder, salt) together in a small bowl and set aside.
In a small sauce pan, over medium heat, melt the butter. Continue cooking it for 3-5 minutes or until the butter is foamy and turns medium golden brown. This process is called browning the butter. Keep a close eye on it because it can burn easily. Remove from the heat, transfer to a medium bowl, and let the butter cool down to room temperature.
When the butter is at room temperature, add in the brown sugar and stir well to combine.
Add the egg, the egg yolk, and the vanilla extract and stir until everything is incorporated again.
Pour the dry ingredients over the wet ingredients and mix just until all the flour has been incorporated. You don't want to over-mix the brown butter blondie mix.
Pour the brown butter blondie mix in the prepared 8X8 inch baking pan, top it with the candied pecans you made earlier and bake for 25-30 minutes. You will know the blondies are done when you insert a tooth pick in the center and it comes out clean or with only a few moist bits.
Cool the candied pecan blondies completely before using the parchment paper to remove them from the baking pan. Slice into 16 equal squares and enjoy.