These adorable Monster Bash Brownies are one of my favorite Halloween treats to make. They’re quick to assemble, delightfully festive, and a great way to get creative with colors and decorations. A sturdy, fudgy brownie base topped with a marshmallow, coated in white chocolate ganache and finished with candy eyes makes a fun handheld dessert perfect for parties, school events, or a festive family night.
It’s a Monster Bash! Customize colors and decorations
Make the monsters your own—change the ganache color, add multiple eyes, use sprinkles or edible glitter, or try different piping designs with gel icing. I made two versions in the photos: bright purple monsters and simple white ghosts. Both are easy and look great on a platter.
These brownies are a playful, eye-catching Halloween dessert that are simple enough for bakers of any skill level. Use them to impress guests or to involve kids in decorating. Because each brownie is individually decorated, it’s a great activity for a Halloween gathering.
Can I use a boxed brownie mix?
The brownie recipe provided below is adapted from King Arthur Flour and produces bakery-style brownies that are both chewy and fudgy—ideal for supporting a marshmallow and coating. That said, a box mix works fine if you’re short on time. If you use a mix, aim for a thicker bake so the brownies can support the toppings: use an 8×8 or 9×9 pan or double a standard box mix to yield thicker brownies.
Key tip: cool the brownies completely before adding the marshmallows and ganache so the marshmallows don’t melt and the ganache sets properly.
Our favorite Halloween tradition: BOOing
A fun tradition we love is “BOOing” neighbors or friends. Make two plates of treats like these Monster Bash Brownies, print a short poem or note to explain the surprise, and leave the treats and note on someone’s porch. When you’re BOOed, display the note in a window or on the door so others know your household has already been included. It’s an easy way to spread Halloween cheer and get everyone into the spirit.
How to make the white chocolate ganache
The ganache is simply hot cream combined with white chocolate chips and a pinch of salt, mixed until smooth. It should be thin enough to pour but thick enough to coat the marshmallows. If you choose to color the ganache, use gel-based food coloring to avoid seizing the chocolate.
Simple cream substitution
The recipe calls for 2 ½ tablespoons of cream. If you don’t want to buy heavy cream for a small amount, substitute with:
- 1 ¾ tablespoons milk + ½ tablespoon melted butter = 2 ½ tablespoons cream
Enjoy!
Alyssa
Other fun Halloween treat ideas
- Monster cupcakes with marshmallow or buttercream decorations
- Quick spooky five-minute fudge
- Mummy-style jalapeño poppers for a savory option
- Halloween-themed floats and drinks
Tip: Pin or save this recipe to make again, and take photos of your creations to remember your favorite decorating ideas.
Monster Bash Brownies
Ingredients
Brownies:
- 10 tablespoons Hershey’s Special Dark cocoa powder
- 2 large eggs
- 8 tablespoons butter
- ¾ cup white sugar
- 6 tablespoons packed brown sugar
- 1 teaspoon vanilla
- ½ teaspoon salt
- ½ teaspoon baking powder
- ¾ cup flour
- 1 cup semisweet chocolate chips
Monster decoration:
- 2 ½ tablespoons cream (or substitute: 1 ¾ tbsp milk + ½ tbsp melted butter)
- ½ cup + 2 tablespoons white chocolate chips
- Pinch of salt
- Gel food coloring (optional)
- 9 large marshmallows
- Candy eyes
- Black gel decorating icing
Instructions
- Preheat the oven to 350°F (175°C). In a large bowl, whisk together the eggs and cocoa powder; set aside. In a microwave-safe bowl, combine the butter and both sugars. Microwave for 90 seconds, stirring every 30 seconds, until melted and combined. Allow the mixture to cool until warm but not hot. Gradually whisk in the egg and cocoa mixture.
- Stir in the baking powder, salt, vanilla, and flour. Let the batter cool slightly, then fold in the chocolate chips.
- Line a 9×9-inch pan with foil and grease the foil or spray with cooking spray. Spread the batter evenly in the pan and bake for 25 minutes. Remove and cool completely before decorating.
- To make the ganache, heat the cream in a microwave-safe bowl for 30 seconds. Add the white chocolate chips and let sit for 1 minute, then stir until smooth. If needed, microwave in additional 15-second intervals until fully melted. Stir in a pinch of salt and gel food coloring if desired.
- Cut the cooled brownies into 9 equal squares. Place a dab of ganache on the bottom of each marshmallow and press the marshmallow onto a brownie. Chill in the refrigerator for 5 minutes to help them set.
- Drop a spoonful of ganache onto the top of each marshmallow and use the back of the spoon to coax the ganache down the sides so the marshmallow is coated and a bit drips onto the brownie. Add candy eyes while the ganache is still wet, then chill until the coating is firm. Use black gel decorating icing to draw mouths, teeth, or other facial details. Serve when fully set.
Nutrition
Share your creations: If you try this recipe, take a photo and keep track of your favorite decorating ideas. These Monster Bash Brownies are a fun, customizable Halloween dessert that pairs well with other themed treats for a party spread.
If you have questions about substitutions, coloring, or decorating techniques, feel free to try different variations—these monsters are meant to be playful and flexible. Enjoy baking and decorating!
Tried this recipe and loved it? Comment and rate it, and don’t forget to save a photo of your finished monsters!