S'mores Brownies are basically the ultimate comfort food. I've seen a ton of recipes where there is a graham cracker crust on the bottom, but I wanted to change things up a bit for these. Since I'm a sucker for a good crumb topping, I got the idea to make a streusel style topping, but using graham crackers.
OK, seriously. Graham cracker streusel? YES. It was so good. It was a little more crumbly than I was expecting, but the warm graham flavor was magnificent. The whole S'mores brownies experience was like a chocolate bomb, but with just enough texture from the streusel and marshmallows to make it practically perfect.
Streusel vs. Crumb Topping
I did some deep-dive Googling on this subject to get the graham streusel the way I was envisioning. I like crumbs that are thick, that hold together and have a little tooth to them. This is in contrast to many "crumb toppings" that are more like, well, crumbly. Kinda loose, small pieces all over the place that always end up falling down your shirt.
So, I found this breakdown of streusel vs. crumb on The Spruce Eats, which you should bookmark right now if you care about your crumbs! The more traditional streusel has a higher fat content, which helps it stick together more so you get nice big crumbs.
You'll want to really crush your graham crackers into super fine pieces, so I recommend a food processor if you have one available. In the photos, though, I just crushed them between two layers of parchment with a rolling pin. (I find basically any excuse to get out of cleaning my food processor.)
After you crush the grahams, just mix them together with the brown sugar and butter. If you're using the food processor, you can just add the sugar and butter to the processor and pulse to combine.
Fudgy Brownie Layer
As for the brownie layer, it's always going to be a fudgy, dense brownie around here. Anything else is classified in our house as a chocolate cake, which is great, but it's not a brownie. You can argue with me on this all day. For real, though. Pretty happy to chat about brownies whenever.
Brownie texture is all about ingredient ratios, just like the streusel. If you have a higher fat-to-flour ratio, the brownies will be fudgy, and as you up the flour they will get more tender and cakier. For these S'mores Brownies, a fudgy layer provides a great contrast to the topping.
Making the S'mores Brownies
To make the batter, you'll start by melting your butter and chocolate together, and then stirring cocoa powder into that warm mixture. You can optionally add a little espresso powder here too. Once it's cooled a bit, you'll mix in your sugar, eggs, vanilla and salt.
Then, you'll add in your flour and chocolate chunks, stirring gently with a spatula until just combined. Dump the batter into your baking pan, spreading it out in an even layer.
Once it's in the pan, take your prepared graham streusel and pinch it together into large streusel crumbs with your fingers, placing each large crumb on top of the brownie batter until you've formed a crumb layer.
Then bake, and after the brownies are done, add the marshmallows on top. Place the tray under the broiler for a few minutes, until the marshmallows look done. Note, do NOT walk away while they are under the broiler! You can also try to toast them with a kitchen torch, but it didn't work so well for me.
That's pretty much it! I think it takes the brownie to a whole new level of decadence. I have to admit that while I love the look of these giant brownie squares, we did cut them up into quarters because they are so rich!
Have you made S'mores Brownies before? Let me know how you liked them in the comments!
- 9"x13" light-colored baking tray
- Parchment paper or nonstick foil to line the tray
- Food processor (optional)
Graham Cracker Streusel
- 120 g graham crackers (about 1 cup/8 graham crackers)
- 50 g brown sugar (¼ cup/1.75 oz)
- 95 g butter (6¾ Tbsp/3.3 oz)
- 227 g butter (8 oz/1 cup/2 sticks)
- 60 g dark chocolate (2 oz) - 60-70%
- 60 g dutch-processed cocoa powder (2 oz/¾ cup)
- 1½ teaspoon espresso powder (optional)
- 400 g sugar (14 oz/2 cups)
- 3 eggs room temperature
- 1 teaspoon vanilla extract
- ½ teaspoon fine grain salt
- 125 g all-purpose flour
- 35 g baking chocolate chunks (¼ cup/1.25 oz)
- 226 g marshmallows (8 oz, about half a 16-oz bag)
- 35 g baking chocolate chunks (¼ cup/1.25 oz)
Make the Graham Streusel
- Crush the graham crackers, either in a food processor or in between layers of parchment paper with a rolling pin. Add to a bowl if you used the rolling pin method.
- Add the sugar to the graham cracker crumbs and mix well (or pulse in the food processor).
- Melt the butter in a small saucepan or in the microwave and pour it on top of the graham mixture.
- Mix by hand or pulse in the food processor until it fully incorporates and will clump together when pinched. You can make this ahead and store it in the fridge for up to a week. (Try not to snack on it!)
Make the Brownie Batter
- Preheat the oven to 350°F (177°C/gas mark 4).
- Prepare a 9"x13" baking tray by spraying it with baking spray and lining it with parchment paper, letting the edges of the parchment stick up over the sides of a pan so you can use it as a sling to remove the brownies from the pan later.
- Melt the butter and chocolate together in a heat safe bowl over a water bath, or in a microwave safe bowl in the microwave. Run the microwave in 10 to 15 second bursts, mixing with a spatula each time the microwave stops.
- Add in the cocoa powder and mix well until combined. You can do the mixing in a stand mixer, with an electric hand mixer or by hand.
- Add the sugar, salt and vanilla extract and mix until combined.
- Add the eggs one at a time and mix until combined.
- A little at a time, add the flour. Gently mix until all the flour is just incorporated.
- Fold in the 35 g of chocolate baking chunks.
- Spread the batter out evenly in the bottom of the pan.
Top with Streusel and Bake
- With your fingers, take a large pinch of the prepared graham cracker streusel and roll it until you get a large crumb that sticks together. Place the large crumb on top of the brownie batter and repeat until you've covered most of the batter.
- Bake for about 35-37 minutes. You can start checking about 5 minutes before that. It will be done when the internal temperature reaches 205°F (96°C).
Add Marshmallows and Chocolate
- Place the marshmallows on top while it is still warm and sprinkle the chocolate chunks over the top as well.
- Turn on the broiler to a low setting and place the baking tray under the broiler. Keep an eye on it as it should not take very long to start melting and toasting the marshmallows.
- When the marshmallows are toasted to your liking, remove the tray from the oven and let the brownies cool in the pan.
Serve and Store
- Use the parchment or foil sling to pull the brownies up and out of the pan and move them to a cutting board. Cut them up into 12 large pieces, about 3" per side. (You might want to cut them smaller, though, because they are super rich!) If you are having trouble getting them out of the pan, you can either cut them directly in the pan or refrigerate them so they firm up.
- You can store these in an airtight container for a week, or wrap individual brownies and freeze.