Halloween Spiderweb Brownies

These Spiderweb Brownies are such a fun dessert for a Halloween party. The brownies are rich and fudgy, and once they’re cool, you stretch melted marshmallow right over the top to make those messy little webs.

And yes, making the webs gets sticky, haha. But that’s kind of the best part. There’s no perfect pattern to follow, so you can pull the marshmallow apart and let it land wherever it wants.

The brownies only need about 20 minutes in the oven, and the webbing is made with just marshmallows and a splash of water. You can bake the brownies ahead, then add the decoration once they’re cool.

Halloween Spiderweb Brownies

These Halloween Spiderweb Brownies have a soft, fudgy center with plenty of dark chocolate flavor. Once they’re cool, melted marshmallow gets stretched over the top to make the web, and the messier it looks, the better!

Print Recipe

PREP: 20 minutes mins

COOK: 20 minutes mins

TOTAL: 40 minutes mins

Servings: 9 brownies

Course: Dessert

Ingredients

  

For the Brownies

• 5¼ oz dark chocolate (150 g), roughly chopped
• 4 tablespoons + 1 teaspoon butter (60 g), cubed
• 1 tablespoon sunflower oil (15 g)
• 2 eggs
• ⅓ cup + 2 teaspoons granulated sugar (75 g)
• ½ cup + 2 tablespoons all-purpose flour (75 g)
• ⅓ cup unsweetened cocoa powder (30 g)
• ¾ teaspoon baking powder (3 g)
• ½ teaspoon vanilla powder
• 1 to 2 tablespoons finely chopped dark chocolate (10 to 15 g), optional

For the Spiderweb

• 4 to 5 large marshmallows (40 to 50 g)
• 1 teaspoon water (5 g)

Instructions

 

1. Preheat the oven to 350°F (180°C). Line an 8 x 8-inch baking pan (20 x 20 cm) with parchment paper, leaving some overhang on the sides so you can lift the brownies out easily.
2. Place the chopped dark chocolate, butter, and sunflower oil in a heatproof bowl. Set it over a saucepan with a small amount of hot water, making sure the bottom of the bowl doesn’t touch the water.
3. Melt the chocolate mixture gently, stirring occasionally, until smooth. Remove it from the heat and let it cool for a few minutes.
4. Add the eggs and sugar to a large bowl. Whisk by hand for about 1 minute, just until combined and the sugar begins to dissolve. There’s no need to whip the eggs.
5. Slowly pour the melted chocolate mixture into the eggs while whisking until evenly combined.
6. Sift in the flour, cocoa powder, baking powder, and vanilla powder. Fold everything together briefly with a spatula, stopping as soon as the batter is smooth and no dry flour remains.
7. Pour the batter into the prepared pan and spread it into an even layer. If using the optional chopped chocolate, scatter it over the top.
8. Bake for 18 to 20 minutes. Insert a skewer into the center to check for doneness. It should come out with a few moist crumbs attached, but no liquid batter.
9. Let the brownie cool completely in the pan. Once cool, lift the whole brownie slab out using the parchment paper and place it on a cutting board. Don’t cut it yet.
10. Place the marshmallows and water in a small heatproof bowl. Set the bowl over a saucepan with a little hot water, making sure the bowl doesn’t touch the water.
11. Stir until the marshmallows become soft, sticky, and stretchy. Remove the bowl from the heat and let the mixture sit for a few seconds. It should still be warm and pliable, but not extremely hot.
12. Take a small amount of marshmallow between your fingers and slowly pull your hands apart to create thin strands.
13. Stretch the marshmallow strands over the whole cooled brownie slab, crossing them in different directions to create the spiderweb effect. Keep going until you’re happy with the coverage.
14. If the marshmallow starts to firm up and becomes difficult to stretch, warm it again over the heat for a few seconds.
15. Let the marshmallow web set slightly, then cut the brownie into squares and serve.

Notes

• Don’t overbake them: A few moist crumbs on the skewer are exactly what you want. If you wait until it comes out completely clean, the brownies can turn out drier.
• Optional chocolate topping: Sprinkle 1 to 2 tablespoons (10 to 15 g) of finely chopped dark chocolate over the batter before baking. You can skip it if you want.
• Melting the chocolate in the microwave: Add the chocolate, butter, and oil to a microwave-safe bowl. Heat for 20 seconds at a time, stirring after each round, until smooth. Let it cool for a few minutes before mixing it with the eggs.
• Melting the marshmallows in the microwave: Add the marshmallows and water to a microwave-safe bowl. Heat for 10 seconds at a time, stirring after each round, until soft and stretchy. Let it sit for a few seconds before touching it because it can get very hot.

Did you make this? Leave a rating below!

These brownies are pretty simple to put together, but the baking time and marshmallow web are the two parts worth watching closely. You can find the full measurements in the recipe card above!

Gather all of your ingredients.

Melt the chocolate: Add the chopped dark chocolate, butter, and sunflower oil to a heatproof bowl. Melt everything gently over a double boiler, stirring now and then, until smooth. Take the bowl off the heat and let the mixture cool for a few minutes before adding it to the eggs.

Mix the eggs and sugar: Add the eggs and sugar to a large bowl and whisk by hand for about 1 minute. You’re not trying to whip in lots of air here. Just mix until the sugar starts to dissolve.

Finish the brownie batter: Slowly pour the melted chocolate mixture into the eggs while whisking. Sift in the flour, cocoa powder, baking powder, and vanilla powder, then fold with a spatula until no dry flour remains. Stop mixing as soon as the batter looks smooth.

Fill the pan: Spread the batter evenly in a parchment-lined 8 x 8-inch pan. If you’re using the optional chopped chocolate, scatter it over the top for little extra pockets of melted chocolate as the brownies bake.

Bake until just set: Bake at 350°F for 18 to 20 minutes. Check the center with a skewer. You want a few moist crumbs attached, but no wet batter. If the skewer comes out completely clean, the brownies may already be heading past that fudgy middle.

Cool completely: Leave the brownie in the pan until it has cooled all the way through. Then use the parchment overhang to lift the whole slab onto a cutting board. Keep it whole for now.

Melt the marshmallows: Add the marshmallows and water to a small heatproof bowl. Warm them over a double boiler until soft and stretchy. Let the mixture sit for a few seconds before handling it.

Make the spiderweb: Take a small amount of warm marshmallow between your fingers and slowly pull your hands apart. Once thin strands form, stretch them over the whole brownie slab. Keep crossing the strands in different directions until the top looks webby enough for you.

Cut and serve: Let the web set slightly and then cut the brownie into squares. Use a sharp knife and wipe the blade between cuts if marshmallow or brownie crumbs start sticking to it. The web will break naturally across the cuts, which gives each piece its own little spiderweb pattern.

Storage and Make-Ahead

Bake the brownies ahead. Make the brownie slab a day in advance, let it cool completely, then keep it covered at room temperature. Add the marshmallow web closer to serving.

Store leftovers covered. Keep the decorated brownies in an airtight container at room temperature for up to 2 days. Place parchment between layers so the marshmallow strands don’t stick together.

Freeze before decorating. If you want to freeze them, do it before adding the marshmallow web. Wrap the cooled brownie slab or individual pieces well, then thaw at room temperature before decorating.

More Halloween Favorites

Planning a Halloween spread? Here are a few more spooky recipes you can add alongside these spiderweb brownies.

Halloween Ghost Taco Hand Pies

Halloween Bat Chips with Salsa and Guacamole

Halloween Mummy Brownie Cookies