These brown butter s'mores bars have a graham cracker and chocolate chip blondie base, sandwiched with gooey marshmallow fluff, and topped with melty Hershey's chocolate bars! They're chewy, gooey, chocolatey, and just so tasty!
The perfect summer dessert for when you're craving s'mores but don't feel like going camping!
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Why You'll Love These S'mores Bars!
- These s'mores bars literally taste just like a s'more in blondie form!
- The marshmallow fluff stays nice and gooey in the center of the bars while the tops get crispy like toasted meringue!
- Adding broken graham crackers to the dough adds extra classic s'mores flavor!
Warning!! Just like actual s'mores, these s'mores bars are super gooey and messy and sticky! The marshmallow filling has a tendency to ooze out of the middle, but that's part of the fun!
You might also like these s'mores donuts, s'mores macarons, or these s'mores cupcakes!
Ingredient Notes
You just need a few ingredients to make these brown butter s'mores bars!
Brown Butter - My favorite ingredient of all time is brown butter!! Brown butter is just unsalted butter that has been melted and gently cooked to bring out a toasty, nutty flavor. If you've never made brown butter before, you can check out this post with all my tips for how to make brown butter! But if you're trying to keep things simple, you can just use regular unsalted butter in the blondies!
Marshmallow Fluff or Creme - These s'mores bars work best with a filling of marshmallow fluff as opposed to regular marshmallows. You can use store-bought marshmallow fluff or creme or you can make your own!
Graham Crackers - Adding broken graham cracker pieces to the dough adds even more classic s'mores flavor! Instead of graham crackers you could substitute digestive biscuits or biscoff cookies.
Hershey's Bars - I like using Hershey's bars in these s'mores blondies because they're so nostalgic and reminiscent of classic s'mores. I like to chop up a couple to mix into the cookie dough, and then leave a few whole to place on top. However, you can use any chopped chocolate bar or even chocolate chips if you prefer!
The complete list of ingredients and amounts is located in the recipe card below.
How to Make S'mores Cookie Bars
Using a stand or hand mixer, cream together the brown butter, brown sugar, granulated sugar until smooth and creamy.
Add in the eggs and vanilla and beat until the texture is light and fluffy (about 3-5 minutes, it should look much paler than before).
Add in the flour, baking powder, and salt and mix until thoroughly combined. The dough should be wet and sticky.
Roughly chop the graham crackers and chocolate bars into small chunks.
Using a spoon or spatula, gently fold in the chocolate chunks and graham cracker pieces.
I love all of my USA Pan cake pans because they are extremely sturdy and truly nonstick. However, I still like to prepare my pans to ensure the s'mores blondies come out easily.
Cut a parchment paper sling slightly smaller than the width of the cake pan and make sure it fits flatly in the bottom. Then lightly spray the bottom and sides of the pan with a vegetable oil based spray. Place you parchment paper sling in the bottom of the pan and smooth it out so that it sticks to the pan spray (you can use metal binder clips to secure it to the pan). After baking you’ll be able to just slide the s'mores bars right out of the pan!
Scoop ¾ of the dough into the bottom of your prepared pan and press down into a nice even layer (you can wet the tips of your fingers to easily flatten out the dough).
Then dollop the marshmallow fluff over the top of the dough, and use a spatula to gently spread it into an even layer.
Take the remaining dough and place flattened pieces on top of the marshmallow layer, allowing spots of the fluff to peek through.
Press some extra graham crackers and chocolate chunks into the top of the dough if desired.
Place in the fridge for 15-20 minutes to firm up slightly before baking.
While the blondies are chilling, preheat the oven to 350°F.
Bake blondies at 350°F for 30-40 minutes or until the top is golden brown and a toothpick inserted in the middle comes out mostly clean.
Remove from the oven and place Hershey's squares on top of the bars. The residual heat will melt them slightly and help them stick to the tops of the bars.
Let the s'mores bars cool fully in the pan, then transfer to the fridge to chill for at least 2 hours before slicing. This makes it so the bars are easier to slice! However, they taste best at room temperature in my opinion (just a lot messier).
When you're ready to slice, use the edges of the parchment paper to slide the s'mores blondies out of the pan.
Note: These bars have been resting at room temperature which is why they're all gooey and messy!
Tips for the Best Brownies!
(and blondies too!)
Use room temperature ingredients! Always make sure ingredients like butter, eggs, milk, etc. are at room temperature before baking (unless the recipe indicates otherwise)! This ensures they'll incorporate into the batter more easily and leads to overall better texture. Remove all ingredients from the fridge 30 minutes to an hour before baking for best results.
Measure your flour correctly! It's most accurate to use a kitchen scale, but if you're measuring by volume you want to spoon and level! Fluff up the flour a bit with a spoon, and then spoon flour into the measuring cup. Once it's overflowing, use the back of a knife to level it off. Don't ever pack flour into the measuring cup or you'll end up with way too much! Improperly measured flour can lead to dry, dense baked goods. Same goes for cocoa powder!
Use an oven thermometer! Just because your oven says it's 350, doesn't mean it is! If you oven hasn't been calibrated recently, it can be as much as 30 degrees off, which will negatively affect all baked goods from cakes to macarons! An oven thermometer is the easiest/cheapest way to ensure your oven is always at the proper temperature.
Use a metal baking pan! Not all materials are created equal when it comes to baking. Metal cake pans conduct heat much better than other materials like glass or ceramic, so your baked goods will cook faster and more evenly!
It's better to undercook the brownies slightly, than overcook them! Brownies will dry out quick, so it's best to err on the side of caution when baking brownies! Bake just until an inserted toothpick comes out mostly clean but still a tad gooey. If you aren't sure, just go ahead and take them out because they'll continue to firm up as they cool. Note: the larger the pan, the less time the brownies will take to cook.
Be patient and let them cool. Warm brownies fresh out of the oven are delish, I know. But it's best to let them fully cool before digging in. The brownies will be less likely to crumble when you cut them and the center is more likely to be fully cooked while still being perfectly fudgy.
Recipe FAQ's
Store blondies in an airtight container in the fridge for up to 5 days. But they taste best if you let them come up to room temperature for about 30 minutes before serving.
To get clean slices of these brown butter s'mores blondies, run a super sharp knife under hot water until the blade is warm, then wipe it dry. Then cut a single slice and repeat. It's a bit tedious to clean the knife before every cut, but you get perfect slices every time!
No, you can use regular unsalted butter if you prefer!
Tips for Success!
For best results I always recommend using weight measurements (especially when baking) because it's the most accurate. Kitchen scales are super affordable and also reduce the number of dishes you have to do! However, all my recipes also include US customary measurements for convince. Use this chart to convert measurements for common ingredients!
Substitutions: In all my recipes, I've included substitutions that I know will work, but I cannot guarantee results if you substitute ingredients that I have not recommended. [For example, granulated sugar and honey are indeed both sweeteners but they have very different properties so they can not always be swapped 1:1. Using honey in a cookie recipe that calls for granulated sugar will yield a giant mess.] In the recipe card you'll find links to the specific ingredients/brands that I use.
A note on salt: I almost exclusively use Diamond Crystal Kosher Salt because it's the best all-purpose salt for cooking and baking. If you're not using kosher salt, consult this handy guide for a conversion chart! When in doubt, if you're using table salt just reduce the amount by half for baked goods. When cooking, I prefer to under-salt because you can always add more! If you've over-salted, adding a little bit of acid (like lemon juice) can help.
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Recipe Card
S'mores Bars
Special Equipment
Ingredients
Cookie Dough
- 1 cup unsalted brown butter, room temperature
- 1 cup light brown sugar
- ½ cup granulated sugar
- 2 large eggs, room temperature
- 2 teaspoons vanilla extract
- 2 cups all purpose flour
- ½ teaspoon baking powder
- ½ teaspoon kosher salt
- 1 cup chocolate chunks
- ½ cup graham cracker pieces
Bars
- 7 ounces marshmallow fluff
- 2 Hershey's bars
- graham cracker pieces
Instructions
- Using a stand or hand mixer, cream together the brown butter, brown sugar, granulated sugar until smooth and creamy.
- Add in the eggs and vanilla and beat until the texture is light and fluffy (about 3-5 minutes, it should look much paler than before).
- Add in the flour, baking powder, and salt and mix until thoroughly combined. The dough should be wet and sticky.
- Roughly chop the graham crackers and chocolate bars into small chunks.
- Using a spoon or spatula, gently fold in the chocolate chunks and graham cracker pieces.
- Cut a parchment paper sling slightly smaller than the width of the cake pan and make sure it fits flatly in the bottom. Then lightly spray the bottom and sides of the pan with a vegetable oil based spray. Place you parchment paper sling in the bottom of the pan and smooth it out so that it sticks to the pan spray (you can use metal binder clips to secure it to the pan). After baking you’ll be able to just slide the s'mores bars right out of the pan!
- Scoop ¾ of the dough into the bottom of your prepared pan and press down into a nice even layer (you can wet the tips of your fingers to easily flatten out the dough).
- Then dollop the marshmallow fluff over the top of the dough, and use a spatula to gently spread it into an even layer.
- Take the remaining dough and place flattened pieces on top of the marshmallow layer, allowing spots of the fluff to peek through.
- Press some extra graham crackers and chocolate chunks into the top of the dough if desired.
- Place in the fridge for 15-20 minutes to firm up slightly before baking.
- While the blondies are chilling, preheat the oven to 350°F.
- Bake blondies at 350°F for 30-40 minutes or until the top is golden brown and a toothpick inserted in the middle comes out mostly clean.
- Remove from the oven and place Hershey's squares on top of the bars. The residual heat will melt them slightly and help them stick to the tops of the bars.
- Let the s'mores bars cool fully in the pan, then transfer to the fridge to chill for at least 2 hours before slicing. This makes it so the bars are easier to slice! However, they taste best at room temperature in my opinion (just a lot messier).
- When you're ready to slice, use the edges of the parchment paper to slide the s'mores blondies out of the pan.
- To get clean slices of these brown butter s'mores blondies, run a super sharp knife under hot water until the blade is warm, then wipe it dry. Then cut a single slice and repeat. It's a bit tedious to clean the knife before every cut, but you get perfect slices every time!
Notes
Nutrition
The nutritional information on this website is only an estimate and is provided for convenience and as a courtesy only. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Kathy says
You were right, these are very messy!! But they were SO good so totally worth the sticky fingers!