Lightly spray the bottom of the pan with non-stick cooking spray, then line with parchment paper leaving an overhang around the sides.
In a large bowl whisk together the butter, brown sugar and white sugar until the sugar is fully incorporated (about 1 minute) and you no longer see pools of melted butter.
Whisk in the egg, egg yolk and vanilla extract.
Gently stir in the flour and salt.
Gently stir in the white chocolate chips.
Spoon half of the batter into the bottom of the pan, then spread to cover the bottom.
Place a layer of golden Oreos on top (4 rows of 4 cookies).
Spoon the rest of the batter over top, and gently spread the batter over top.
Bake in the preheated oven for about 30-35 minutes, or until the top is set and the sides are starting to pull away from the sides of the pan and an inserted toothpick comes out clean or with a few damp crumbs. Bake time will depend on your oven and how gooey you like your blondies.
Cool fully in the pan (about 4 hours). Then pull the bars out of the pan using the overhang of the parchment paper. Place on a cutting board and cut with a large, sharp knife.
Notes
Eggs: You will need 2 eggs for this recipe, but only use the egg yolk from the second egg. Discard the white.
Nutrition: Details provided are an estimate only and based on 1 very large blondie, assuming the pan is sliced into 9 equal blondies. I often slice each of the 9 blondies in half.
Storage: Store blondies in an airtight container at room temperature for up to 4 days.