Preheat oven to 350℉. Prepare an 8x8 pan with cooking spray and parchment paper.
In a small saucepan, melt butter over medium heat. Whisk until foamy and browned with a nutty aroma. Whisk frequently, making sure not to burn. Once browned, remove from heat and transfer browned butter to a bowl to cool (don't forget to keep all of those brown bits in the mix!).
In a large bowl, whisk together flour, brown sugar, baking powder, and salt.
Add in brown butter, bourbon & egg, whisking thoroughly to fully combine.
Fold in chocolate chunks and scoop into greased and lined 8x8 pan. Top the blondies with some more chocolate chunks and bake for 20-25 minutes.