The Ultimate Gooey Chocolate Chip S’mores Cookie Bars (Trust Me, You Need This)

These s’mores cookie bars combine a chewy chocolate chip cookie base with graham cracker pieces, chocolate wafers, and toasted mini marshmallows, all baked in a single 8×8 pan using a two-step bake that keeps the marshmallows perfectly gooey instead of melting away. Total time is about 38 minutes, and the payoff is campfire flavor with zero campfire required.

What do you get when you smash two classic favorite desserts together?

You get this chocolate chip s’mores cookie bar. It is gooey, chewy, delicious, and super easy, too. We are bringing all the best parts of a campfire indoors, right into an 8×8 pan!

Why You Will Love These S’mores Cookie Bars

• Two Desserts in One: It is the ultimate mashup. You get the chewy, comforting base of a chocolate chip cookie paired with the gooey, toasted magic of a classic s’more.
• Lower Sugar: The sugar in this recipe is low because we are adding plenty of sweet mix ins. Stick to the ratio!
• Minimal Cleanup: We are basically just going to mix everything into one bowl. Less time doing dishes, more time eating.
• That Toasted Top: We use a special two step baking process (and maybe a creme brulee torch) to get that perfect fire roasted marshmallow finish.

If you love an easy, one-bowl dessert bar like this one, you are also going to want to try my Easy Key Lime Pie Bars, another simple pan dessert that comes together with minimal fuss and maximum payoff.

What You Will Need

Special Equipment

• 8×8 inch metal baking pan
• Parchment paper, to create a sling for easy removal
• Mixing bowls and sturdy spatula
• Creme brulee kitchen torch, optional but highly recommended for toasting

For the Cookie Dough Base

• 1/2 cup (1 stick) unsalted butter, melted
• 1/2 cup light brown sugar, packed
• 1/4 cup granulated white sugar, reduced for perfect sweetness!
• 1 large egg plus 1 large egg yolk (save the white for breakfast!)
• 1 tsp vanilla extract
• 1/2 tsp baking soda
• 1/2 tsp salt
• 1 1/4 cups all purpose flour

For the S’mores Mix Ins and Toppings

• 1 cup semi sweet or dark chocolate wafers (Ghirardelli or Trader Joe’s preferred), divided
• 1 cup mini marshmallows, divided
• 3 to 4 full graham cracker sheets, broken into various sizes

Let us Get Baking!

1. Prep Your Pan

Preheat your oven to 350°F (175°C). Line an 8×8 inch baking pan with a parchment paper sling. I do not do all four sides because there is really no need to. Leaving an overhang on two sides means you can always just lift the bars right out by the flaps.

2. The Sugar and Butter Situation

All right, so get all of your ingredients and you are ready to go. Have a little bit of white granulated sugar, and some brown sugar. In a large mixing bowl, combine the melted butter, brown sugar, and granulated white sugar. Give everything a good mix!

Quick tip: Brown sugar tends to clump up, so if that happens to you, just break it apart with your whisk or spatula.

3. Eggs and My Secret Baking Trick

Now, add one egg and one yolk. Just save the egg whites for breakfast tomorrow! Give it another good mix. After you whisk the eggs into the butter and sugar, the consistency should be very thin and smooth, and that is perfect because you have all of the rest of the stuff to add in.

Next, add salt, baking soda, and vanilla extract. Add the baking soda and salt into the wet ingredients. A lot of times, you will see those components mixed with the dry ingredients, but I personally find that this makes for a much better, chewy cookie base. It is just a technique and preference. Always aim to put the vanilla extract right on top of the baking soda just to activate it, and then give everything a thorough mix.

4. The Fun Stuff (Chocolate, Marshmallows, and Grahams)

Now, pour in the all purpose flour and the star ingredients:

• Chocolate chips: I use 1/2 cup of chocolate wafers instead of traditional chips. They are not like the chips with the pointy tops; they are more flat and round. You can find them by Ghirardelli. If you can find these, definitely use them! I prefer semi sweet or dark chocolate here.
• Mini marshmallows: Because, of course, s’mores needs 1/2 cup of marshmallows!
• Graham crackers: For that classic campfire crunch. Break them up into various sizes, some really small ones, some big ones, so that way, you get a good amount in every single bite.

Give it a final mix. Get some elbow grease in there and fold everything together with a spatula until just combined!

5. Into the Pan and The Two Step Bake

Transfer the pliable dough to your prepared 8×8 pan. The dough at this point is super pliable, so just use your spatula to flatten it out into an even layer.

Now, the baking process goes in two crucial steps. First, bake this in the oven at 350°F for exactly 8 minutes. You definitely do not want it totally done yet. It should still be jiggly and very raw in the center. This is on purpose!

6. The Ultimate Topping

When you pull it out after 8 minutes, you will see the high points of the marshmallows inside the batter starting to brown up, but it is very much still raw.

Right now, immediately top with the remaining 1/2 cup of mini marshmallows right on top. You can add as much or as little as you would like, along with the remaining 1/2 cup of chocolate wafers. Return to the oven for another 4 to 5 minutes. By this point, the cookie base itself should be fully baked and set, no longer wet or jiggly. The gooeyness you are aiming for at this stage comes from the melted marshmallow and chocolate, not from undercooked batter.

7. The Golden Finish and How to Cut It

Here is a quick pro tip! During the last 30 seconds or so of baking, turn on your oven broiler so that the tops of the marshmallows brown up beautifully. Never step away from the oven during this step, since broilers can go from perfectly golden to burnt (or even catch stray marshmallow bits on fire) in just a few seconds. Or, alternatively, remove them from the oven and use a creme brulee torch. Torching the top to give it that nice, burnt, fire roasted look is even better. If you use a torch, keep the flame moving constantly, never point it toward yourself or anyone else, and work in a ventilated space away from anything flammable. I do not have one, but if you do, definitely do that!

Let the bars cool in the pan for at least 10 minutes until you are ready to cut. Lift them out using the parchment sling. Using a sharp knife, I like to cut it into thirds both ways so you get nine generous pieces. It is ooey gooey licious. When you are cutting it, just do it in one firm go by pressing straight down. Do not drag your knife, because things can get messy.

This is a messy food, but embrace it! Serve it warm, and if you really want to wow everyone, throw a scoop of vanilla ice cream right on top. Enjoy!

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The Ultimate Gooey Chocolate Chip S’mores Cookie Bars

Recipe by Sana Rei

0.0 from 0 votes

Course: DessertCuisine: AmericanDifficulty: Easy

Servings

9

large bars

Prep time

15

minutes

Cooking time

13

minutes

Calories

310

kcal

Chill time

10

minutes

Total time

38

minutes

Smash two classic desserts together! These chewy chocolate chip cookie bars are loaded with graham crackers, dark chocolate wafers, and gooey fire-roasted marshmallows, all made in one bowl and one 8×8 pan.

Ingredients

• Equipment Needed:

• 8×8 inch baking pan

• Parchment paper

• Mixing bowl

• Spatula

• Kitchen torch, optional

• Ingredients:

• 113g (1/2 cup) unsalted butter, melted

• 100g (1/2 cup) light brown sugar, packed

• 50g (1/4 cup) granulated white sugar

• 1 large egg

• 1 large egg yolk

• 1 tsp vanilla extract

• 1/2 tsp baking soda

• 1/2 tsp salt

• 150g (1 1/4 cups) all-purpose flour

• 170g (1 cup) semi-sweet or dark chocolate wafers, divided

• 50g (1 cup) mini marshmallows, divided

• 3 to 4 full graham cracker sheets, broken into various sizes

• Vanilla ice cream, optional, for serving

Directions

• Preheat oven to 350°F (175°C). Line an 8×8-inch baking pan with a parchment paper sling.
• In a large bowl, mix the melted butter, brown sugar, and granulated sugar until well combined. Break up any brown sugar clumps.
• Whisk in the whole egg and the egg yolk until the batter becomes thin and smooth.
• Add the baking soda and salt to the bowl. Pour the vanilla extract directly onto the baking soda, then mix everything together.
• Fold in the flour, half the chocolate wafers, half the mini marshmallows, and the broken graham crackers until just combined.
• Press the dough evenly into the prepared pan using a spatula.
• Bake for 8 minutes. The center will still be raw and jiggly on purpose.
• Remove from the oven and scatter the remaining marshmallows and chocolate wafers across the top.
• Return to the oven and bake for another 4 to 5 minutes, until the cookie base itself is fully set and no longer wet, with only the marshmallow and chocolate remaining gooey.
• Optional: broil for the final 30 seconds without leaving the oven unattended, or use a kitchen torch after removing from the oven, to get a fire-roasted marshmallow top.
• Let cool for 10 minutes. Slice by pressing a sharp knife straight down without dragging. Serve warm.

Notes

• The Chocolate Swap: Ghirardelli or Trader Joe’s chocolate baking wafers instead of standard chips are highly recommended. The flat shape melts beautifully into gooey puddles.
• The Two-Step Bake: Do not skip it. If all the marshmallows go on from the very beginning, they will melt away and disappear. Adding them at the 8-minute mark keeps them perfectly gooey and intact.
• Doneness Check: By the end of baking, the cookie base itself should be fully set and no longer wet or jiggly. Any remaining gooeyness should come from the melted marshmallow and chocolate, not undercooked batter.
• Torch and Broiler Safety: If using a kitchen torch, keep the flame moving, never point it at yourself or others, and work in a ventilated area away from anything flammable. If using the broiler, never leave the oven unattended, since broilers can burn food or ignite marshmallow bits within seconds.
• Slicing Pro-Tip: Run a sharp chef’s knife under hot tap water, wipe it dry, and press straight down. Do not drag the knife.
• Allergen Note: Contains gluten, dairy, and eggs.
• Storage: Airtight container at room temperature for up to 3 to 5 days. Freeze individually wrapped bars for up to 2 months.
• Nutrition: Calories are estimated and will vary based on chocolate wafer brand and marshmallow amount.