Prepare the Oven and Pan:Preheat your oven to 350°F (175°C). Grease or line an 8x8-inch baking pan with parchment paper.
Mix the Wet Ingredients:In a mixing bowl, combine the melted and cooled unsalted butter with brown sugar and white sugar. Mix until well combined.
Incorporate Eggs and Vanilla:Add the egg, egg yolk, and vanilla extract to the butter-sugar mixture. Mix until smooth and creamy
Combine Dry Ingredients:In a separate bowl, sift together the all-purpose flour, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Fold in Additions:Gently fold in the white chocolate chips, ensuring they're evenly distributed throughout the batter.
Prepare the Oreos:Arrange 16 Golden Oreos at the bottom of the prepared baking pan in a single layer.
Layering the Batter:Pour the blondie batter evenly over the Oreo layer in the pan, making sure to cover them entirely.
Bake to Perfection:Place the pan in the preheated oven and bake for 30-35 minutes or until the top turns golden brown, and a toothpick inserted in the center comes out clean or with a few moist crumbs.
Cool and Serve:Once baked, remove the pan from the oven and allow the blondies to cool completely in the pan on a wire rack.
Slice and Celebrate:When cooled, lift the blondies from the pan, slice them into squares, and get ready to enjoy these delightful Birthday Oreo Blondies!
