Preheat oven to 350 degrees F. Line a 9-inch by 13-inch baking pan with foil and spray with a non-stick cooking spray.
If the butter hasn’t been melted, melt the butter and set it aside to completely cool before using.
12 tablespoons unsalted butter
Once the butter is cooled, whisk the flour, baking powder, and salt. Set aside.
1 ½ cups all-purpose flour, 1 teaspoon baking powder, ½ teaspoon kosher salt
Place the 9 Oreos into a plastic bag and crush the cookies with a rolling pin or other hard object. A food processor could also be used, pulse the cookies a few times to break them into pieces. Cut the extra 2-3 Oreos into pieces. Set aside. In a large bowl, whisk together the melted butter (make sure this is cooled!) and brown sugar. Add eggs and vanilla extract; mix until combined. Using a spoon or spatula, fold in dry ingredients. Don’t over mix. 1 cup packed light brown sugar, 2 large eggs, 1 tablespoon vanilla extract
Fold in the white chocolate chips and Oreos.
½ cup white chocolate chips, 3/4 cup crushed Oreo cookies
Spoon the batter into pan, spreading the dough out over the bottom of the pan. Top with some extra white chocolate chips and the cut Oreos.
Bake 22-25 minutes, or until a toothpick inserted into the middle comes out clean.
Place pan on a wire rack to cool. Once cooled, remove by pulling the edges of the foil and move to a cutting board. Cut into 28 pieces.