Bring all the flavors of a campfire favorite into one easy dessert with these Ultimate Sheet Pan S’Mores Bars. They start with a buttery graham cracker crust, topped with rich fudgy brownies, then finished with gooey toasted marshmallows, crunchy graham crackers, and plenty of melted chocolate.
They’re everything you love about traditional s’mores without standing around a fire roasting marshmallows one at a time.
Whether you’re hosting a backyard barbecue, family celebration, or holiday picnic, this easy sheet pan dessert feeds a crowd and disappears fast. The combination of crunchy, chewy, fudgy, and gooey textures makes every bite irresistible.
Even better, you can easily customize the toppings with your favorite candy bars, peanut butter cups, cookies, or flavored marshmallows to create your own signature version.
Why You’ll Love This Recipe
- Perfect dessert for feeding a crowd
- Easy shortcut using boxed brownie mix
- Ready with simple pantry ingredients
- Great make-ahead dessert
- Easy to customize with favorite candy bars
- Rich, fudgy, gooey, and crunchy in every bite
- Perfect for summer parties, potlucks, and family gatherings
Ultimate Sheet Pan S’Mores Bars for Summer Gatherings
As an Amazon Associate I earn from qualifying purchases.
Kitchen Essentials
Ingredients
Graham Cracker Crust
- 3 Cups Graham Cracker Crumbs about 3 sleeves
- 2/3 Cup Butter melted
- 6 Tablespoons Granulated Sugar
Brownie Layer
- 32.6 Ounces Brownie Mix 2 boxes (9×13 size)
- 2 Tablespoons Water
- ½ Cup Vegetable Oil
- 2 Large Eggs
S’Mores Topping
- 6 Cups Mini Marshmallows
- 6 Graham Cracker Sheets broken into pieces
- 1 Cup Milk Chocolate Chips
- 4 Chocolate Bars broken into squares
Instructions
How to Make Sheet Pan S’Mores Bars
- Preheat oven to 350°F.
- Grease a standard half-sheet pan generously with butter or baking spray.
- In a medium bowl, combine the graham cracker crumbs, melted butter, and sugar. Mix until the mixture resembles wet sand.3 Cups Graham Cracker Crumbs, 2/3 Cup Butter, 6 Tablespoons Granulated Sugar
- Press firmly into an even layer across the bottom of the pan.
- Bake for 10 minutes. Remove from the oven.
- Prepare both brownie mixes according to the package directions. In a large bowl, combine the brownie mix, water, oil, and eggs. Mix until well combined.32.6 Ounces Brownie Mix, 2 Tablespoons Water, ½ Cup Vegetable Oil, 2 Large Eggs
- Pour the batter evenly over the warm crust. Spread gently to the edges.
- Bake for 30 to 35 minutes, or until a toothpick inserted near the center comes out with only a few moist crumbs.
- Then add the toppings. Sprinkle evenly with: mini marshmallows, graham cracker pieces, chocolate chips, and chocolate bar pieces.6 Cups Mini Marshmallows, 6 Graham Cracker Sheets, 1 Cup Milk Chocolate Chips, 4 Chocolate Bars
- Move the pan to an upper oven rack.
- Broil for 2 to 3 minutes, watching constantly until the marshmallows are puffed and golden brown.
- If you love extra toasted marshmallows, broil another 30 seconds—but don’t walk away.
- Cool completely at room temperature.
- For even cleaner slices, refrigerate for about 20 minutes before cutting.
- Slice into 24 squares and serve.
Your Own Private Notes
Notes
Recipe Tips
- A standard half-sheet pan (18 x 13 inches) works best for this recipe. Line the pan with parchment paper for even easier removal.
- Press the graham cracker crust firmly into the pan so it doesn’t crumble when sliced.
- Bake the crust first so it stays crisp beneath the brownies.
- Do not overbake the brownies. Slightly fudgy brownies create the best texture.
- Watch the broiler every second. Marshmallows brown incredibly fast.
- Spray your knife with cooking spray before each cut.
- Wipe the knife clean between slices.
- Let the brownies cool before adding to the refrigerator.
- Use parchment paper for easy removal.
- Don’t skip baking the crust first—it helps prevent a soggy bottom.
Nutrition
Delicious Variations
Classic Campfire
Top with mini marshmallows and Hershey chocolate pieces.
Peanut Butter Lover
Replace Hershey bars with chopped peanut butter cups and use large marshmallows cut into chunks.
Cookies and Cream
Top with crushed chocolate sandwich cookies and white chocolate chips.
Salted Caramel
Add caramel bits and finish with flaky sea salt after broiling.
Triple Chocolate
Use dark chocolate chips, milk chocolate bars, and white chocolate drizzle.
Mint Chocolate
Add chopped mint chocolate candy and crushed chocolate mint cookies.
Storage
Store leftovers in an airtight container.
- Room temperature: up to 2 days
- Refrigerator: 4 to 5 days
The marshmallows become a little chewier after refrigeration but are still delicious.
Can You Freeze Them?
Yes.
Allow the bars to cool completely.
Wrap individual pieces in plastic wrap and place them inside a freezer-safe container.
Freeze for up to 2 months.
Thaw overnight in the refrigerator or let sit at room temperature for about an hour before serving.
What to Do with Leftovers
These bars are fantastic:
- Warmed for 10–15 seconds in the microwave.
- Crumbled over vanilla ice cream.
- Packed into lunch boxes.
- Served with hot chocolate or coffee.
- Chopped into bite-sized pieces for a dessert tray.
Can I make these ahead of time?
Yes. Bake them the day before your event and store them covered. For the freshest marshmallow texture, add the toppings and broil shortly before serving if possible.
Can I use homemade brownies?
Absolutely. Use your favorite brownie recipe that fills a 9×13-inch pan and double it for a half-sheet pan.
Can I use different candy bars?
Yes. Try:
- Reese’s Peanut Butter Cups
- Snickers
- Milky Way
- Heath Bars
- Kit Kat
- Cookies and cream chocolate bars
Why did my marshmallows burn?
Broilers cook extremely fast. Stay by the oven and watch continuously.
Can I use jumbo marshmallows?
Yes. Cut them into quarters so they toast evenly.
How do I get clean slices?
Cool completely, refrigerate for about 20 minutes, then use a lightly greased knife, wiping it clean after every cut.
Serving Ideas
These bars are perfect for:
- Summer cookouts
- Family reunions
- Camping trips
- Birthday parties
- Graduation celebrations
- Holiday gatherings
- Church potlucks
- Bake sales
- School events
Summertime Desserts
Sometimes the sweetest memories are made over a pan of warm brownies, toasted marshmallows, and plenty of laughter.
My family loved this! Great for our summer gatherings. The kids love it. Quick and Easy to serve.