01 -
Preheat the oven to 350°F. Line a 9 by 13-inch baking dish with parchment paper, leaving an overhang for easy removal. Lightly grease the parchment with butter or nonstick spray.
02 -
In a large bowl, whisk together melted butter, granulated sugar, and brown sugar until the mixture is smooth and glossy. Add eggs one at a time, whisking well between each addition, then incorporate the vanilla extract.
03 -
In a separate bowl, sift together cocoa powder, all-purpose flour, baking powder, and salt. Gradually incorporate the dry ingredients into the wet mixture, stirring until just combined. Fold in chocolate chips if desired—do not overmix.
04 -
Spread half of the brownie batter evenly into the prepared pan. Arrange Oreos in a single layer over the batter, maximizing coverage. Gently spread the remaining brownie batter over the Oreos and smooth the surface with a spatula.
05 -
Bake for 35 to 40 minutes, or until a toothpick inserted in the center yields a few moist crumbs. Remove the pan from the oven and allow brownies to cool completely on a wire rack.
06 -
Melt white chocolate or candy melts in a microwave-safe bowl in 30-second increments, stirring until smooth. Divide into separate bowls and tint with orange and purple coloring. Drizzle colored chocolate over the cooled brownies. While the chocolate is wet, add Halloween sprinkles and candy eyeballs as desired. Allow the topping to set for 20 to 30 minutes.
07 -
Carefully remove brownies from the pan using the parchment overhang. Cut into 16 squares with a sharp knife, cleaning the blade between each cut for neat edges. Arrange on a platter for festive presentation.