Ingredients

2/3 cup unsalted butter, melted

1/4 cup vegetable oil

1 cup granulated sugar

1/3 cup brown sugar

2 large eggs, cold

1 tsp pure vanilla extract

2/3 cup unsweetened cocoa powder, sifted

1/2 cup all-purpose flour, spooned and leveled

1/2 tsp salt

15 Oreo cookies, coarsely crushed

1 cup unsalted butter, softened (for frosting)

4 cups powdered sugar, sifted (for frosting)

1/2 tsp pure vanilla extract (for frosting)

3-4 tbsp milk or heavy cream (for frosting)

Green gel food coloring (for frosting)

Pinch of salt (for frosting)

5 Halloween-themed Oreo cookies (for topping)

Edible candy eyes (for decoration)

Assorted Halloween sprinkles (optional)

Melting chocolate (white or dark, optional, for decoration)

Instructions

Step 1: Preheat your oven to 350°F (175°C). Line a 9×13 inch baking pan with parchment paper, leaving an overhang for easy removal, and lightly grease the paper.

Step 2: Melt 2/3 cup butter and let it cool slightly. In a large bowl, whisk together the melted butter with 1 cup granulated sugar and 1/3 cup brown sugar until smooth. Beat in the 2 cold eggs one at a time, then stir in 1 tsp pure vanilla extract.

Step 3: In a separate bowl, whisk together 2/3 cup sifted unsweetened cocoa powder, 1/2 cup all-purpose flour, and 1/2 tsp salt until combined.

Step 4: Gradually add the dry ingredients to the wet ingredients, mixing just until combined—avoid overmixing. Gently fold in the 15 coarsely crushed Oreo cookies for extra texture.

Step 5: Pour the batter evenly into the prepared pan. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with moist crumbs. Be careful not to overbake. Let the brownies cool completely on a wire rack for 1-2 hours.

Step 6: To make the frosting, beat 1 cup softened unsalted butter until light and fluffy. Gradually add 4 cups sifted powdered sugar, 1/2 tsp vanilla extract, a pinch of salt, and 3 to 4 tablespoons milk, beating until smooth and spreadable. Mix in green gel food coloring until you reach a spooky hue.

Step 7: Once the brownies are fully cooled, spread the green buttercream evenly over the top. Arrange 5 Halloween-themed Oreo cookies on the frosting, then decorate with edible candy eyes and optional Halloween sprinkles or drizzles of melted chocolate for a spooky finish.

Step 8: Chill the decorated brownies in the refrigerator for at least 30 minutes to set the frosting and allow for clean slicing. Use a hot, clean knife to slice and serve. Store leftovers in an airtight container at room temperature for up to 3 days, or in the refrigerator for up to a week.

Tips & Variations

Use room temperature eggs for a smoother batter if you prefer, but cold eggs work fine and add extra structure.

Swap green gel food coloring for other colors like purple or orange for different Halloween themes.

For a richer frosting, replace some milk with heavy cream.

If you want a less sweet brownie, reduce the granulated sugar by 1/4 cup.

Add a handful of chopped nuts for extra crunch inside the brownies.

Storage

Store these brownies in an airtight container at room temperature for up to 3 days. For longer freshness, keep them refrigerated for up to one week. When ready to serve, you can bring refrigerated brownies to room temperature or enjoy them cold. To reheat, warm individual slices gently in the microwave for 10-15 seconds.

FAQs

Can I use regular Oreos instead of Halloween-themed ones?

Yes, regular Oreos work great for both inside the batter and as toppings. Halloween-themed Oreos just add extra festive fun.

Can I make the brownies gluten-free?

You can substitute the all-purpose flour with a gluten-free flour blend that measures cup for cup. Make sure your other ingredients are gluten-free certified for best results.