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S’mores Brownie Bars: Gooey, Easy, and Totally Irresistible

S’mores Brownie Bars: Gooey, Easy, and Totally Irresistible

The Messy, Chocolatey Story Behind These Bars

You know how some recipes just follow you around forever? S’mores Brownie Bars are that for me. I first made these because I wanted to impress my nephew at a family BBQ. He was more interested in playing with sticks, but (surprise!) the adults hovered around the kitchen and nearly inhaled the whole pan before the kids even saw it. Anyway, I’ve been making them ever since—sometimes for parties, sometimes on a random Tuesday. And if we're being honest, sometimes just 'cause I needed a chocolate fix. Funny thing, every batch looks a little different, which I secretly love.

Why You'll Love This (Or Maybe Just Crave It Sometimes)

I make this when my sweet tooth is hollering and I can’t decide between brownies or s’mores. Or when I want to look like I tried really hard, but didn’t. My family goes a bit bonkers for these—my brother once hid three bars in the microwave and acted like he couldn’t find them (nice try, mate). If you’ve ever tried to toast marshmallows with a lighter (don’t), this recipe will save your dignity. Plus, it’s easy to double, though you might regret it when you realize you ate half the pan yourself. Don’t ask me how I know.

Stuff You'll Need: Ingredients & My Lazy Substitutions

  • 1 box brownie mix (18–20 ounces) (I’ve tried Ghirardelli, but store brand is fine—no judgement!)
  • Eggs, oil, and water, as called for on your box (or whatever the package says—sometimes I throw in a splash of cold brew; it's amazing)
  • 2 cups graham cracker crumbs (about 16 crackers smashed up; my grandma insisted on Honey Maid, but Ritz will do in a pinch—seriously)
  • ½ cup melted butter (unsalted, but I’ve used salted and honestly, it’s fine)
  • 2 cups mini marshmallows (or big ones cut up with scissors when I forget to buy minis, but that’s sticky chaos)
  • 1 to 1.5 cups semi-sweet chocolate chips (milk chocolate if you want it super sweet, or use chunks from a leftover chocolate bunny; no, really)

Here’s How You Throw These Together

  1. Preheat your oven to 350°F (175°C), unless you forgot, in which case do it now. Line a 9x13 inch pan with foil or parchment. Or just grease it with butter—I've forgotten both, and it still worked.
  2. Mix your graham cracker crumbs and melted butter. Press this sandy stuff into the bottom of your pan. Don’t stress if it looks uneven—nobody’s checking.
  3. Prepare your brownie batter as the box says. Once, I accidentally used too much water and it still tasted great (just a bit fudgier). Pour this over your crumb base. Spread it out (a spatula helps, but a big spoon is fine, or just tilt the pan and hope for the best).
  4. Bake for about 25 minutes. This is my favorite part—my kitchen smells like a campfire and a bakery had a baby. Don’t overbake! Stick a toothpick in the center; if it comes out with a few crumbs, it’s ready. Or just guess. It’s brownies, not a science fair.
  5. Sprinkle all the marshmallows on top and scatter chocolate chips over them. Pop the pan back in the oven for another 5–7 minutes. Marshmallows should get puffy and a little golden. Sometimes mine brown unevenly—totally normal.
  6. Let the bars cool a bit. This is where I usually sneak a corner, burn my tongue, and regret nothing. If you want neat slices, let ‘em cool completely (I almost never do).

Notes from My Experiments (& Occasional Disasters)

  • If you forget to line the pan, just soak it in hot water later. Trust me.
  • I once tried using those marshmallow fluff jars—honestly, too gooey. Stick to real marshmallows.
  • The bars are easier to cut if you stick them in the fridge for 30 minutes. Or just embrace the mess.
  • Actually, I find it works better if you underbake by a minute or so. Fudgier is always better here.

Things I’ve Tried (And a Few Flops)

  • Peanut butter swirl on top: brilliant.
  • Crushed pretzels in the graham layer: also ace.
  • Adding banana slices: Nope, wouldn’t recommend (got weirdly soggy).
  • I saw someone online add caramel bits—on my to-try list! If you want ideas, check Sally’s Baking Addiction—she’s got loads of wild combos.

Don’t Sweat It: Gear and Workarounds

You technically need a 9x13 pan, but I’ve squished this into an 8x8 before—just bake a bit longer. No mixer? No problem—whisk or even a sturdy fork works. The only thing I’d say is sort of non-negotiable: you need something to press the graham crumbs down (even your hands, but wash them, yeah?). Oh, and for the record, I don’t own a fancy offset spatula, just a good old butter knife.

S’mores Brownie Bars

How to Store (Though They Rarely Last That Long)

Keep leftovers in an airtight container at room temp for up to 3 days. But honestly, in my house it never lasts more than a day! If you do want to make them ahead (I admire your willpower), you can freeze them, though the marshmallows can get a bit weird in texture. King Arthur Baking has tips on freezing brownies, if you’re curious.

How We Eat ‘Em (Feel Free to Copy or Ignore)

I like mine warmed up with a scoop of vanilla ice cream—my cousin dunks hers in coffee. At summer parties, we slice them small and let everyone grab a square with sticky fingers. Once, we topped them with sprinkles for a birthday, and the kids went nuts (rainbow sprinkles do make everything better, don’t they?).

Lessons Learned (Sometimes the Hard Way)

  • Let the bars cool before cutting, or you’ll have a chocolate-marshmallow avalanche. I once tried rushing this step and regretted it because the whole middle just oozed out.
  • Don’t use wax paper in the oven. It smokes like mad. Oops.
  • Taste the crumbs before pressing them in—sometimes the crackers are a bit stale (ask me how I know).

Questions Folks Usually Ask Me (Or Text at 10pm)

  • Can I make these from scratch instead of using a mix? Absolutely! Sometimes I do when I have extra time. I use this brownie recipe—it’s fab, but honestly, the box mix is my weeknight MVP.
  • Can I use vegan marshmallows? Yep, works fine—just check they melt okay. Some brands act weird (they kinda just sit there and refuse to toast).
  • What if I don’t have graham crackers? Digestive biscuits, vanilla wafers, or even plain old animal crackers work in a pinch. Heck, I used a mix once, and nobody noticed.
  • Can I double this? Yessir, just use two pans (or one huge lasagna tray if you’re feeling bold—but watch the bake time).
  • Why do my marshmallows get so sticky? That’s just life, mate. Wet your knife a bit before cutting, helps a treat.
  • Is it normal if mine look... rustic? Oh absolutely. If you want perfection, you’re in the wrong kitchen! Rustic = more homemade, right?

Anyway, that’s how I do S’mores Brownie Bars. If you give it a go, let me know how yours turn out—or if you hide a few for yourself, I won’t judge. Pinky swear.

★★★★★ 4.80 from 162 ratings

S’mores Brownie Bars

yield: 12 servings
prep: 20 mins
cook: 35 mins
total: 55 mins
A decadent dessert bar that combines the classic flavors of s’mores with rich, fudgy brownies. Layers of graham cracker crust, chocolate brownie, and toasted marshmallows make this treat irresistible for any occasion.
S’mores Brownie Bars

Ingredients

  • 1 ½ cups graham cracker crumbs
  • ⅓ cup unsalted butter, melted
  • ¼ cup granulated sugar
  • 1 box (18 oz) brownie mix
  • 2 large eggs
  • ½ cup vegetable oil
  • ¼ cup water
  • 2 cups mini marshmallows
  • ½ cup semi-sweet chocolate chips

Instructions

  1. 1
    Preheat the oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper.
  2. 2
    In a medium bowl, combine graham cracker crumbs, melted butter, and granulated sugar. Press the mixture evenly into the bottom of the prepared pan to form the crust.
  3. 3
    Prepare the brownie mix according to package instructions using eggs, oil, and water. Pour the brownie batter over the graham cracker crust and spread evenly.
  4. 4
    Bake for 30-35 minutes, or until a toothpick inserted into the center comes out mostly clean.
  5. 5
    Remove the pan from the oven and immediately sprinkle mini marshmallows and chocolate chips evenly over the top. Return to the oven for 3-5 minutes, or until marshmallows are golden and puffy.
  6. 6
    Let cool completely before slicing into bars. Serve and enjoy!
CLICK FOR NUTRITION INFO

Approximate Information for One Serving

Serving Size: 1 serving
Calories: 320 caloriescal
Protein: 3gg
Fat: 14gg
Saturated Fat: 0g
Trans Fat: 0g
Cholesterol: 0mg
Sodium: 0mg
Potassium: 0mg
Total Carbs: 46gg
Fiber: 0g
Sugar: 0g
Net Carbs: 0g
Vitamin A: 0
Vitamin C: 0mg
Calcium: 0mg
Iron: 0mg

Nutrition Disclaimers

Number of total servings shown is approximate. Actual number of servings will depend on your preferred portion sizes.

Nutritional values shown are general guidelines and reflect information for 1 serving using the ingredients listed, not including any optional ingredients. Actual macros may vary slightly depending on specific brands and types of ingredients used.

To determine the weight of one serving, prepare the recipe as instructed. Weigh the finished recipe, then divide the weight of the finished recipe (not including the weight of the container the food is in) by the desired number of servings. Result will be the weight of one serving.

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