Fudgy, chewy brownies swirled with peanut butter and baked over a sweet graham cracker crust, then topped with toasted marshmallows, melty chocolate, and more graham cracker crumbs. Peanut Butter S’mores Brownies are the perfect summer treat!
Have you ever made a s'more with peanut butter or a peanut butter cup?! It truly is delicious! This recipe combines everything you love about s'mores wrapped up in a brownie, plus some delicious peanut butter to really seal the deal!
Made with melty chocolate, crunchy graham crackers, toasty marshmallows, and my favorite brownie recipe. They're addicting!
These are easy to make and are so delicious served warm, just as you would with a s’more. And you know what goes perfectly with a fudgy brownie? A tall glass of cold milk!
Why you'll love S'mores Brownies
- Fun summer treat. S'mores are a summer staple and I love combining them with one of my favorite chocolate desserts: brownies!
- Easy to make. Yes, there is layering involved, which requires a little more time and effort but these brownies are still really simple to make!
- Extra delicious with peanut butter. Peanut butter adds a delicious layer of creamy, salty flavor that I can't get enough of!
- Graham crackers
- Butter (I like to use salted)
- Vegetable oil
- Granulated sugar
- Brown sugar
- Vanilla extract
- All-purpose flour
- Unsweetened cocoa powder
- Peanut butter, smooth or crunchy
- Chocolate bars (such as Hershey's)
- Miniature marshmallows
How to make Peanut Butter S'mores Brownies
Making peanut butter s'mores brownies requires a couple of extra steps compared to making regular brownies, but it's so worth the extra effort!
- Graham cracker crust. This step is easy! Lay graham crackers in the bottom of the baking dish in a single layer.
- Brownie filling. Start by creaming together your wet ingredients, then mix in the dry. Once you add the dry ingredients, be careful not to overmix. Pour over the graham crackers then swirl with peanut butter.
- Bake the brownies. Bake until a toothpick comes out mostly clean. It's perfectly OK for a little bit of fudgy crumb to stick to the toothpick. They'll finish cooking as they cool, resulting in perfectly fudgy brownies.
- S'mores toppings. Once the brownies have finished baking, top with marshmallows, along with more chocolate and graham cracker pieces then broil in the oven for about 1 minute. Watch closely so the marshmallows don't burn!
*Scroll down to the recipe card for the full instructions.
Frequently asked questions
What's the difference between fudge brownies and regular brownies?
Fudge brownies are more moist and gooey in the center, and personally my favorite!
What makes brownies fudgy instead of cakey?
Fudgy brownies are made with an equal or greater than ratio of fat to flour. Meaning, you'll use equal parts flour and fat, such as butter or oil, or more fat than flour. For my chewy, fudgy brownie recipe, I like to use ¾ cup butter, ¼ oil and 1 cup of flour, equaling out the fat to flour ratio.
Cakey brownie recipes will call for more flour than fat to create a brownie that more closely resembles the spongy texture of cake.
Are brownies better with butter or oil?
A combination of both butter and oil makes the perfect brownies. Butter is much more flavorful than oil, but it also solidifies once it cools, whereas oil remains a liquid. So, to keep the brownies moist and fudgy even after they cool, I like to use a little oil, but mostly butter, in my brownies.
Can I leave out the peanut butter?
If peanut butter isn't your thing, you can simply skip it. The brownies will still be delicious!
Can I used boxed brownie mix?
Yes, you certainly can, but I prefer homemade! Prepare the box mix as directed and pour over the graham crackers. Bake as directed on the box, then top add the toppings and broil.
How to store Peanut Butter S'mores Brownies
Cover the brownies tightly with plastic wrap, aluminum foil, or a lid at room temperature for up to 3-4 days.
To make the brownies ahead of time, prepare one day in advance according to the instructions below. However, I recommend waiting to add the marshmallows and additional chocolate and graham cracker pieces on top until the day of serving.
- Line the baking dish with parchment paper. Not only does this prevent the brownies from sticking to the baking dish, but it also makes cutting the brownies a whole lot easier! Grab the long edges of the parchment paper to lift the brownies from the baking dish, then slice and enjoy!
- Spray your knife with cooking oil! Toasted marshmallows can be sticky and difficult to cut, so I recommend spraying your knife with cooking oil (or rubbing with cooking oil) as needed to prevent sticking.
- Don't overtake the brownies. A toothpick inserted in the center should come out mostly clean but with some fudgy crumbs. The brownies will continue to bake and setup as they cool.
- Watch the brownies closely under the broiler. You don't want burnt marshmallows, so watch closely - this should only take a minute or two.
More recipes you'll love
If you enjoyed this recipe, please leave a ⭐️⭐️⭐️⭐️⭐️ rating and a comment below! I'd love to hear from you! If you’re on Instagram, share a picture of the food you created and tag me at Modern Farmhouse Eats! I enjoy seeing all the pictures! 😊
Peanut Butter S'mores Brownies
- 9-10 graham crackers
- ¾ cup butter, melted (1½ sticks)
- ¼ cup vegetable oil
- 1 cup granulated sugar
- 1 cup packed brown sugar
- 4 eggs
- 1 teaspoon vanilla extract
- 1 cup all-purpose flour
- 1 cup unsweetened cocoa powder
- ½ teaspoon salt
- ½ cup peanut butter, smooth or crunchy
- 2 chocolate bars, roughly chopped (about ½ cup)
- 1-2 cups miniature marshmallows
- Preheat oven to 350° F. Line 9x13 inch baking dish with parchment paper, allowing some parchment to hang over the edges of the pan.
Graham cracker crust
- Arrange the graham crackers in a single layer in the bottom of the baking dish, breaking some crackers to fill the space.
Peanut butter brownie
- In a large bowl, whisk together melted butter, vegetable oil, and sugar for 1 minute. Add eggs and vanilla extract and whisk until combined and lighter in color.
- Add the flour, cocoa powder, salt and ¼ cup of chopped chocolate to the bowl with the wet ingredients. Using a sturdy spoon, fold in the dry ingredients until just combined.
- Pour the batter over the graham crackers and spread into an even layer. Drop dollops of peanut butter over the batter, then use a butter knife to swirl the peanut butter.
- Bake for 25-30 minutes, or until a toothpick inserted into the center comes out mostly clean with some crumbs, but not wet batter.
- Top with the mini marshmallows, remaining ¼ cup of chopped chocolate, and 1-2 crumbled graham crackers.
- Position a rack in the top ⅓ of the oven, and broil the brownies for about 1 minute, or until the marshmallows are golden brown (watch closely as they can burn quickly).
- Remove from oven and let cool for 30 minutes. Use the edges of the parchment paper to lift the brownies from the baking dish, then slice and enjoy! Tip: Spray your knife with cooking oil to prevent the marshmallows from sticking to the knife when slicing!