01 -
Line a 9x13 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
02 -
In a medium saucepan or microwave-safe bowl, melt the unsalted butter completely and allow it to cool slightly.
03 -
Whisk granulated sugar into the melted butter until the mixture is glossy and fully combined.
04 -
Incorporate eggs one at a time, whisking well after each addition, then stir in the vanilla extract.
05 -
Using a fine-mesh sieve, sift together all-purpose flour, unsweetened cocoa powder, and salt directly into the wet mixture.
06 -
Gently fold the dry ingredients into the wet mixture using a spatula, mixing just until combined and no flour remains.
07 -
Add two-thirds of the chocolate chips and two-thirds of the chopped Halloween Oreo cookies to the batter, folding until just distributed.
08 -
Pour the batter into the prepared baking pan, spreading it evenly with a spatula.
09 -
Place the reserved Oreo cookie pieces and whole Halloween Oreos on top, pressing gently into the batter. Scatter reserved chocolate chips evenly across the surface.
10 -
Bake at 350°F (177°C) for 30-35 minutes, or until the center is just set and a toothpick inserted comes out with a few moist crumbs.
11 -
Allow brownies to cool completely in the pan on a wire rack. For clean slices, refrigerate for 30 minutes, then use a large chef’s knife to cut into squares, wiping the blade between slices.