Gooey S’mores Blondies with Marshmallow Fluff

S’mores Blondies – ​These bars are layered with chewy blondie, rich ganache, and a cloud of toasted marshmallow fluff—basically, everything you love about classic s’mores without the smoke

Okay, confession time: I hate bagged marshmallows. Like, why are they always weirdly stiff and flavorless? And after living in the city for four years without a fire pit, s’mores just weren’t happening. Even when they were, the whole fire pit thing? It’s a no from me. I’m not trying to smell like smoke for the next three days. So instead, I made an actually good version. These gooey s’mores blondies are soft, rich, layered, and way more delicious than anything on a stick. Think elevated s’mores bar—but make it cute.

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Why You’ll Love These Gooey S’mores Blondies

No campfire? No problem.

• All the flavors of classic s’mores, no fire pit needed
• Made with a rich blondie base packed with graham cracker crumbs
• Topped with smooth ganache and fluffy homemade marshmallow
• The toasted top adds that smoky finish without smelling like a bonfire
• A serious upgrade from anything made with bagged marshmallows
• Easy to slice and store—perfect dessert for parties or late-night cravings

Ingredients – S’more Blondies

Here’s everything you’ll need to make the most extra s’mores blondie bars ever.
(No camp chair required.)

• Unsalted butter – melted for that rich, gooey blondie texture
• Brown sugar & granulated sugar – classic duo for deep sweetness
• Egg + egg yolk – helps create that chewy blondie bite
• Vanilla extract – adds warmth and balances the chocolate
• Baking powder, salt & cornstarch – your dry ingredients dream team
• All-purpose flour – the foundation of the blondie batter
• Graham cracker crumbs – brings the graham cracker crust flavor into every bite
• Heavy whipping cream – for the dreamy chocolate ganache
• Semi-sweet chocolate – rich, melty chocolate layer to mimic Hershey’s bars
• Egg whites, granulated sugar, Karo syrup, water, salt, vanilla – for your homemade marshmallow fluff (or just use store-bought if you’re not about that sugar syrup life)

Step-by-Step Instructions

• Preheat oven to 350°F. Line an 8×8 metal baking pan with parchment paper, leaving overhang for easy lifting.
• Melt the butter and let it cool slightly.
• In a large bowl, whisk melted butter with brown sugar and granulated sugar until combined.
• Add in the egg, egg yolk, and vanilla. Whisk until smooth.
• Fold in flour, baking powder, salt, and cornstarch just until combined—don’t overmix.
• Stir in graham cracker crumbs until evenly mixed into the blondie batter.
• Spread into the prepared pan and bake for 23–25 minutes, until the edges are golden brown and a toothpick comes out with a few moist crumbs.
• Let the blondies cool completely before topping.

These s’mores blondies get even better after they’ve chilled, so don’t rush it!

For the Ganache

• In a microwave-safe bowl, heat heavy cream until hot and steamy (but not boiling).
• Add semi-sweet chocolate and let sit for 5 minutes. Stir until smooth.
• If needed, microwave in short bursts to fully melt.
• Pour over cooled blondies and spread evenly across the entire surface. Chill in the fridge to set.

For the Marshmallow Fluff

• In a stand mixer bowl, whisk egg whites and a pinch of salt on low until frothy.
• In a small saucepan, combine granulated sugar, corn syrup, water, and vanilla. Heat to 240°F (soft ball stage).
• With mixer on medium-high, slowly drizzle the hot syrup down the side of the mixing bowl.
• Once added, crank the speed to high and whip for 5 minutes or until stiff and glossy.
• Spread fluff over chilled ganache and use a kitchen torch to toast the top.

Tips and Tricks

• If you don’t want to make homemade fluff, go ahead and use a 7 oz jar of store-bought. Still delish.
• Measure your flour correctly – Spoon the flour into your measuring cup and level it off with a knife. Don’t scoop straight from the bag—it packs it down and gives you way too much flour, which can make your blondies dry instead of chewy.
• Use parchment paper for easy removal – Line your pan with a sheet that has some overhang so you can lift the whole thing out cleanly.
• Room temperature ingredients matter – Let your eggs sit out for 15–30 minutes before baking. Cold eggs don’t mix as easily and can mess with the texture.
• Let the blondies cool completely – Seriously, don’t rush this step. If they’re even a little warm when you pour the ganache, it’ll slide right off instead of setting into a smooth layer.
• Ganache too thick? – Add a splash of warm cream and stir until it thins out.
• No thermometer? – For the marshmallow fluff, you’ll know your syrup is close to 240°F when it starts to bubble thickly and slowly drip from a spoon like warm honey.
• Torch-less toasting – No kitchen torch? Pop the finished bars under the broiler for 30–60 seconds. Watch it like a hawk so it doesn’t burn.
• Use a plastic knife or hot knife to cut – These are sticky bars. A warm knife (run it under hot water and wipe dry) helps you get clean slices.
• Chill for cleaner cuts – The longer these s’mores blondies sit in the fridge, the neater they slice. Overnight is ideal if you’re making them ahead.
• Don’t overmix the batter – Once the flour goes in, switch to a spatula and fold just until you don’t see streaks of flour. This keeps them soft and tender.

FAQs – S’mores Blondies

• Can I make these ahead of time?
  Yes! You can make them 1–2 days in advance and store in an airtight container in the fridge.
• Do I have to use a kitchen torch?
  Nope, but it’s fun. You can pop the finished bars under the broiler for 30 seconds—just watch them closely.
• Can I add peanut butter or other mix-ins?
  Go for it! A swirl of peanut butter or milk chocolate chips would be amazing in the blondie layer.
• Is it okay to use store-bought fluff?
  Yes. No judgment here. Just make sure it’s fresh and easy to spread.

Recommended Tools

• 8×8 metal baking pan
• Parchment paper
• Kitchen torch for that toasted top
• Food processor for graham cracker crumbs
• Stand mixer or electric hand mixer
• Small saucepan & thermometer for fluff-making

Storing and Freezing Instructions

• Store leftovers in an airtight container at room temp for 1–2 days or in the fridge for up to 5.
• Freeze (unglazed or fully finished) in a single layer, then stack with parchment paper between bars.
• Thaw overnight in the fridge and bring to room temp before serving.

This Gooey S’mores Blondies is a delicious recipe to add to your weekend baking list. You’ll get classic S’mores taste with no campfire, no camping, but just pure time in the kitchen! 

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Recipe

Smores Blondies

Molly Murphy

easy cookie bars filled with graham cracker crumbs, chocolate ganache, and homemade toasted marshmallow fluff!

5 from 2 votes

Print Recipe Pin Recipe

Course Dessert

Cuisine American

Servings 9 squares

Ingredients

 

US CustomaryMetric

 

1x2x3x

FOR THE BLONDIES

• ½ cup unsalted butter
• ½ cup brown sugar
• ⅓ cup granulated sugar
• 1 egg room temperature
• 1 egg yolk room temperature
• 1 teaspoon vanilla
• ½ teaspoon baking powder
• ¼ teaspoon baking soda
• ½ teaspoon salt
• ½ teaspoon corn starch
• 1 cup all-purpose flour
• ½ cup graham cracker crumbs

FOR THE GANACHE

• ¾ cup heavy whipping cream
• 1 ½ cups semi sweet chocolate

FOR THE MARSHMALLOW FLUFF

• Note: you can just buy a 7 ounce jar of marshmallow fluff if you don’t want to make your own
• 2 egg whites room temperature
• 1 Pinch of salt
• 3 tablespoons granulated sugar
• ½ cup light karo syrup
• 2 tablespoons water
• 1 teaspoon vanilla extract

Instructions

 

FOR THE BLONDIES

• Preheat your oven to 350°F (175°C). Prepare an 8×8 inch baking pan by greasing it or lining it with parchment paper, leaving some overhang for easy removal.
• In a microwave-safe bowl or on the stovetop, melt the unsalted butter until fully melted. Allow it to cool slightly.
  ½ cup unsalted butter
• In a large mixing bowl, whisk together the melted butter, brown sugar, and granulated sugar until well combined.
  ½ cup brown sugar, ⅓ cup granulated sugar
• Whisk in the egg, followed by the egg yolk, and vanilla extract to the butter and sugar mixture. Mix well until smooth and creamy.
  1 egg, 1 egg yolk, 1 teaspoon vanilla
• Using a rubber spatula, fold in the all-purpose flour, baking powder, salt, baking soda and cornstarch into the wet ingredients mixture until just combined. Do not overmix.
  ½ teaspoon baking powder, ¼ teaspoon baking soda, ½ teaspoon salt, ½ teaspoon corn starch, 1 cup all-purpose flour, ½ cup graham cracker crumbs
• Gently fold in the graham cracker crumbs until evenly distributed throughout the batter.
• Pour the blondie batter into the prepared baking pan. Use a spatula to spread it out evenly.
• Place the pan in the preheated oven and bake for 23-25 minutes, or until the edges are golden brown and a toothpick inserted into the center comes out with a few moist crumbs attached.
• Once baked, remove the pan from the oven and allow the blondies to cool completely in the pan. While the blondies are cooling, make the ganache.

FOR THE GANACHE

• Place the cream in a medium microwave-safe bowl and heat until hot and slightly bubbly, ensuring it doesn’t boil over. Start with 30-second intervals, checking until bubbly.
  ¾ cup heavy whipping cream, 1 ½ cups semi sweet chocolate
• Remove from the microwave and add the chocolate. Let the mixture sit for 5 minutes without stirring. If the chocolate hasn’t fully melted after 5 minutes, microwave again in short intervals until smooth.
• Once ready, stir until everything melts and the mixture is smooth. Pour the ganache over the cooled blondies and spread evenly. Place in the fridge to firm up while making the marshmallow fluff.

FOR THE MARSHMALLOW FLUFF

• In the bowl of a standing mixer, use a whisk to combine the egg whites and salt until frothy. Keep the mixer on the lowest speed to maintain stability.
  2 egg whites room temperature, 1 Pinch of salt
• In a small saucepan, combine the sugar, corn syrup, and water over medium heat. Heat until the sugar is fully dissolved, reaching about 240°F (115°C) or the soft ball stage, about 3-5 minutes.
  3 tablespoons granulated sugar, ½ cup light karo syrup, 2 tablespoons water
• Once the sugar has melted, turn the mixer to medium-high speed and slowly pour the hot sugar mixture down the inside rim of the mixing bowl, letting it run down the side slowly. Pour very slowly to avoid scrambling the eggs. This process should take about 2 minutes.
• Once all the sugar has been added, add the vanilla and increase the mixer speed to high and beat for about 5 minutes or until the mixture is very stiff and shiny.
  1 teaspoon vanilla extract
• Gently spread the marshmallow fluff on top of the ganache layer. Using a kitchen torch, carefully toast the top of the marshmallow fluff until lightly browned. Ensure safety by keeping flammable materials away and maintaining a safe distance from the flame.

Keyword smore, marshmallow

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