I had been wanting to make this cake for months, ever since I came up with the idea of a graham cracker pie crust for my Strawberry & Graham Cracker Layer Cake. This weekend, I finally felt like the moment was right. I’m not sure how I waited so long but I’m sorry I did because this cake is definitely up there with the best. In two words, it’s a s’mores cake. In better words, it’s a s’mores cake piled high with toasted marshmallows, oozing with chocolate ganache and marshmallow frosting between layers of graham cracker pie crust and fudgey chocolate cake. One of my cousins actually compared it to Mallomars – if you don’t know what those are, I’m so sorry. Click here to find out what you’re missing. I thought that was a pretty spot-on comparison and you could easily call this a Mallomar Cake instead of a S’mores Cake, if you’re so inclined. Thank god my (very big) family finished the whole thing, because I would not have been able to resist the leftovers, had there been any.
To make the cake, instead of coming up with anything new I just took parts of a bunch of old recipes and remixed them into one fabulous new cake. I didn’t initially intend on blogging it so I don’t have too many pictures, and to supplement, I stole some pictures from previous posts. It’s the chocolate cake from my first S’mores Cake, the graham cracker pie crust from my Strawberry & Graham Cracker Layer Cake, and a marshmallow frosting similar to the one from my Chocolate Toasted Marshmallow Layer Cake. Put it all together, drown it in ganache, and pile some toasted marshmallows on top – voilà!
Here we go:
Start by making the graham cracker pie crust. Grease two 9″ cake pans and line the bottoms with parchment paper, then grease some more. Mix together graham cracker crumbs (I usually buy them in crumb form rather than crushing my own), sugar, cinnamon, and melted butter. Press it into the bottom of the cake pans, using the bottom of a glass to make sure it’s evenly packed down. Bake for 7 minutes on 325. I usually try and do this step the day before to save myself some time when I’m making the cake.
Next, make the cake batter. Sift dry ingredients together in a bowl. Using an electric mixer, mix buttermilk, oil, eggs, and vanilla on high speed until combined. Slowly add the dry ingredients to the wet ingredients with the mixer on low. Once fully combined, with the mixer still on low speed, add the hot coffee until combined. Then pour the batter evenly into the two cake pans, on top of the pie crust. Bake for around 35 minutes on 350.
Removes the cakes from the oven when a toothpick inserted in the center comes out clean. Let cool in the pans on a wire rack for 10 minutes and then remove from the pans and allow to cool completely.
Make the marshmallow frosting. Whip room temperature butter on medium-high until it’s light and fluffy, then add marshmallow fluff and continue to mix on medium-high for another 2-3 minutes. Add vanilla and mix until combined. Add 2 cups of confectioner’s sugar, one at a time. Mix on medium-high for 5 minutes. If you think the frosting is too thin, at this time add more confectioner’s sugar until the frosting reaches desired consistency.
Optional – add in toasted marshmallows. I toasted 6-8 large marshmallows in the oven until they were lightly browned and then added them into the frosting immediately after removing them from the oven. It adds to the flavor and consistency, though you might end up with some little pieces of toasted marshmallow throughout the frosting. I think adding the toasted marshmallows is a nice touch, but the frosting would be totally fine without it.
Make the chocolate ganache – literally the easiest thing to do in all of baking. Heat up the heavy cream in a microwave safe container or on the stove, until it’s almost boiling but not quite. Dump the chocolate chips into the cream and let it sit for 5-10 minutes. Then mix until the chocolate and cream are combined, silky, and smooth, and allow it to sit some more. The only slightly tricky part of this is figuring out when the ganache is the right temperature to pour over the cake, but more on that in a minute. Cake assembly time.
Optional – if your cake layers are very domed, slice a little off the tops to even them out. A flatter cake usually looks more polished/professional. Put the first layer on your cake plate, graham cracker side up. Spread with a thick layer of frosting. Since the sides of this cake don’t get frosted, you can use up to half of the frosting on the middle layer. I think 1/2 of the frosting would probably be a little too much, but too much frosting never killed anybody (well, I guess that’s debatable). Now toast your mini marshmallows in the oven until browned the way you like them, and put a layer on top of the frosting.
I tried to keep the layer as flat and neat as I could but it turned into somewhat of a mess, since marshmallows are so sticky. I don’t have a picture, but don’t worry about it if yours comes out messy too. Then put the second layer of cake on top, also graham cracker side up. When I did this some marshmallow oozed out of the center, but I think it only adds to the effect of the cake. Then top with remaining frosting (or however much you want).
Now for the ganache – you want the consistency to be thin enough that you can easily pour it and spread it so that it starts to drip down the sides of the cake, but not so liquidy that it just runs right off the top. Ideally, the ganache will harden as it’s dripping down the sides. If you get to this step and the ganache has cooled too much and is too thick, just pop it back in the microwave for 10-15 seconds. When I made this cake the ganache was a little thicker than I would have wanted it to be when I poured it on. It didn’t drip down the sides as much as I wanted, but it still looks and tastes great!
Allow the ganache to dry a little bit, and then top with big toasted marshmallows. I toasted them with the oven on broil until lightly browned and then piled them on top of the cake, pretty haphazardly. S’mores are a messy dessert so there’s nothing wrong with a messy s’mores cake! (Sorry again for the lack of photos, and the ugly one below)
Toasted Marshmallow S'mores Cake
- 2 1/4 cups graham cracker crumbs
- 1/2 cup granulated sugar
- 8 tbs (1 stick) unsalted butter, melted
- 3/4 tsp cinnamon
- 1 3/4 cups flour
- 1 3/4 cups granulated sugar
- 3/4 cup unsweetened cocoa powder
- 1 teaspoon baking powder
- 2 teaspoons baking soda
- 1 teaspoon salt
- 1 cup buttermilk, room temperature
- 1/2 cup vegetable oil
- 2 large eggs, room temperature
- 1 teaspoon vanilla extract
- 1 cup freshly brewed strong hot coffee
- 1 cup (2 sticks) butter, room temperature*
- 1 (7oz) jar of Marshmallow Fluff or marshmallow creme
- 2-3 cups confectioner’s sugar
- 1 teaspoon vanilla
- Optional – 6-8 large marshmallows
- 1/2 cup heavy cream
- 1 cup semi-sweet chocolate chips
- 1-1.5 cups mini marshmallows
- ~20 large marshmallows
- For the graham cracker pie crust: Preheat the oven to 325 degrees. Mix together graham cracker crumbs, butter, sugar, and cinnamon. Cut circles of parchment paper to fit the bottoms of two 9″ cake pans and lightly grease the pans, under and on top of the parchment paper, and the sides. Then press half of the graham cracker mixture evenly into the bottom of each pan. You can use the bottom of a glass or other flat object to make sure the graham cracker crumbs are well pressed. Bake for 7 minutes, and then allow to cool. If desired, this step can be completed a day ahead of time.
- For the cake: Preheat the oven to 350 degrees. Sift together the flour, sugar, cocoa powder, baking powder, baking soda, and salt in a medium sized bowl and set aside.
- In the bowl of a stand mixer, mix buttermilk, oil, room temperature eggs, and vanilla on high speed until combined. With the mixer on low, slowly add the dry ingredients to the wet ingredients. Slowly add in hot coffee and continue mixing on low until combined.
- Pour the batter into the prepared pans and bake for 35 minutes or until a toothpick inserted in the center comes out clean. Allow cakes to cool on wire rack for 10 minutes and then remove from pans.
- For the frosting: Cream the butter with an electric mixer on medium-high speed for 2-3 minutes, until light and fluffy. Add the marshmallow fluff and mix on medium-high for another 2-3 minutes. Add the vanilla extract and 1 cup of confectioner’s sugar and mix until fully incorporated. Then add another cup of confectioner’s sugar and beat on medium-high for 5 minutes. If the frosting is too thin at this point, add more sugar until it reaches desired consistency.
- Optional for the frosting: With the oven on broil, toast 6-8 large marshmallows on a parchment lined baking sheet. It can take less than a minute for the marshmallows to brown, so watch them the whole time. Take them out when they’re a nice golden color and mix them into the frosting immediately, whipping until fully combined.
- For the ganache: Heat the cream in the microwave or in a saucepan over the stove, until steaming hot but not boiling. Remove from heat and dump the chocolate chips into the cream. Let sit for 5 minutes, and then whisk until silky and smooth. Allow to cool while assembling the cake.
- Cake assembly: If your cake layers are rounded, slice off the domed parts so you have nice flat tops. Place one cake layer on a cake plate, graham cracker side up. Top with 1/3-1/2 of the frosting. Now toast mini marshmallows until golden brown, using the same method as described in step 6.** Transfer them to the cake and lay them on top of the frosting as evenly as possible but don’t worry if it turns into a mess!
- Wait for the marshmallows on the bottom layer to cool first if you want to minimize oozing, although I like the oozing effect. Then place second layer of cake on top, graham cracker side up. Top with remaining frosting or desired amount. Place cake in refrigerator to set for 10-15 minutes.
- Pour ganache over the cake. You want the ganache to be thin enough to pour, but thick enough that it will dry as it drips down the sides of the cake. If the ganache has cooled too much and is too thick, reheat it in the microwave for 10-15 seconds. As you pour the ganache onto the cake, use a spatula to spread it around and push it towards the edges so it can begin to drip down.
- Top with large toasted marshmallows. Toast about 20 large marshmallows on a parchment lined baking sheet, removing from the oven when they are golden brown. As soon as you remove the tray from the oven, slide the parchment sheet off of the tray onto a table or countertop so they can cool. Once the marshmallows are cool, arrange them on top of the cake any way you like. I did one layer of marshmallows, staying about 1/2 inch away from the edges, and then placed a few more marshmallows on top.
* Use either 1 stick of unsalted butter and 1 stick of salted butter, or 2 sticks of salted butter. If you do not have salted butter, add salt to taste.
**The photo in this post shows the mini marshmallows on aluminum foil. It’s an old photo; I’ve found that parchment paper works better.