Ingredients (and Why They Matter)
Brownie Layer
- 1 cup unsalted butter, melted
- 2 cups granulated sugar
- 1 cup packed brown sugar
- 4 large eggs
- 1 tablespoon vanilla extract
- 1 cup unsweetened Dutch-processed cocoa powder
- 1 cup all-purpose flour
- 1/2 teaspoon baking powder
- 1/2 teaspoon salt
- 1 cup semi-sweet chocolate chips (optional)
Melted butter plus sugar and cocoa follows the same base method as many fudgy brownie recipes that start with whisked melted butter and cocoa instead of melted chocolate. Using both granulated and brown sugar adds moisture and chew, a trick often used in dense brownie formulas. Dutch‑processed cocoa gives a deeper chocolate flavor and darker color, which stands out nicely against the bright Halloween drizzles. Chocolate chips are optional but match other “loaded” Oreo brownies that fold chips into the batter for extra pockets of melted chocolate.
Oreo Layer
- 20 to 24 Halloween Oreos or classic Oreos
A full layer of Oreos in the center mimics other Oreo-stuffed brownie bars where cookies are laid in a single layer between two layers of batter. Halloween Oreos add orange filling and seasonal patterns, but classic ones work the same structurally.
Festive Topping
- 1 1/2 cups white chocolate or white candy melts
- Orange food coloring or orange candy melts
- Purple food coloring or purple candy melts
- Halloween-themed sprinkles
- Candy eyeballs (optional)
- Crushed Oreos for garnish (optional)
White chocolate or candy melts create a smooth, colorful drizzle that sets firm, similar to the way Halloween brownie and bark recipes decorate with tinted chocolate and sprinkles. Using pre-colored orange and purple melts makes coloring easier and avoids seizing from water-based color. Candy eyeballs and themed sprinkles are standard Halloween decor items that instantly signal the holiday on brownies and bars.
Step-by-Step Instructions
Preheat the oven to 350°F (175°C). Line a 9×13‑inch baking dish with parchment paper, leaving an overhang on the long sides for easy lifting, and lightly grease the parchment; this setup is the same one used in many layered brownie bar recipes.
In a large bowl, whisk together the melted butter, granulated sugar, and brown sugar until the mixture is smooth and glossy, which is a typical cue in cocoa‑based brownies to show sugar and fat are well combined. Whisk in the eggs one at a time, mixing well after each, then whisk in the vanilla extract; beating eggs well helps create a shiny top and good structure, as noted in many fudgy brownie methods.
In a separate bowl, sift together the cocoa powder, all-purpose flour, baking powder, and salt. Gradually stir the dry ingredients into the wet mixture until just combined—overmixing is discouraged in brownie recipes because it can create a cakier texture. Fold in the semi-sweet chocolate chips if using.
Spread half of the brownie batter evenly into the prepared pan, smoothing it into the corners. Arrange the Oreos in a single layer over the batter, maximizing coverage; this “full cookie layer” approach matches other Oreo-stuffed brownies that aim for a cookie in every bite. Gently spread the remaining brownie batter over the Oreos and smooth the surface with a spatula, taking care not to dislodge the cookies.
Bake for 35–40 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs but no wet batter, which is the classic doneness indicator for fudgy brownies. Remove the pan from the oven and let the brownies cool completely on a wire rack; many decorated brownie recipes stress full cooling before adding any melted chocolate topping.