Ultimate S'mores Cake With Toasted Marshmallow Fluff Frosting

This S'mores Cake is three moist cake layers of graham cracker cake, filled with toasted marshmallow frosting, graham cracker crumble, and milk chocolate ganache. One bite of this cake and you'll be transported straight back to your summer campfire.

I didn't want this S'mores cake to just look like a giant S'more, I really wanted it to FEEL like you're biting right into a freshly toasted S'more. To achieve this, not only did I include actual graham cracker crumbs that give you that satisfying crunch but I also added toasted marshmallow fluff to the buttercream and more toasted marshmallows to the top of the cake. The more you toast them, the more flavor you will have in your buttercream. This is the secret ingredient to the ultimate S’mores cake!

Did you know? The "S" in S'mores is short for "some more" as in "give me some more of that yummy dessert!" Originally called a graham cracker sandwich. It became very popular with boy scouts and girl scouts and soon after, an American tradition.

S'mores Cake Ingredients

Graham Crackers: No S'mores cake is complete without some graham crackers. To me, Honey Maid graham crackers are the only choice but feel free to use any graham crackers you like.

Hershey’s Chocolate: Again, we are going with that classic S'mores flavor and to me, nothing but Hershey's milk chocolate will do but again, you can use any kind of chocolate that you really like. If you want more chocolate flavor inside your cake, sprinkle some chocolate chips in between the layers with the graham cracker crumbs.

Marshmallow Fluff: This is the secret to the best tasting S'mores cake! You can buy a jar of marshmallow creme from the store and toast it just like regular marshmallows. Marshmallow fluff is much softer than a regular marshmallow so it's easy to mix into your buttercream.

Tips For Success

1. Is this your first time decorating a cake? Watch my free video tutorial on how to decorate a cake for the first time.
2. This cake uses a mixing method called the reverse creaming method. The dry ingredients are coated in the butter before being mixed with the liquid ingredients and you mix for much longer than you do with a traditional mixing method.
3. Use a kitchen scale to weigh your ingredients for the best results. Baking is a science!
4. I used a stand mixer to make my cakes but you can also use a hand-held electric mixer. If you use a hand-mixer then you may need to mix for longer to achieve the same batter consistency.
5. Room temperature ingredients are important. Make sure your buttermilk and eggs are slightly warm and your butter is soft but not melted so that your ingredients mix together properly.
6. I like using a kitchen torch to toast my marshmallows but if you don't have one you can toast them in the broiler the same as you do with the fluff.

How to Make S'mores Cake

There are 4 different components of this cake, the graham cracker cake, graham cracker crumble, toasted marshmallow buttercream, and chocolate ganache. I recommend making the cake layers a day in advance, or at least first so that they have time to cool.

Making The Graham Cracker Cake

1. Preheat your oven to 350º F and prep three 6-inch cake pans (or two 8-inch pans) with cake goop or your preferred pan release. 
2. Add your milk, eggs, yolks, vegetable oil, and vanilla into a small bowl. Give it a quick whisk with a hand whisk and set aside. 
3. Add your flour, sugar, crushed graham crackers, baking soda, baking powder, and salt into the bowl of your stand mixer with the paddle attachment. 
4. Mix your flour mixture for a couple of seconds on low speed to incorporate all the ingredients together.
5. Add your room temperature butter to your flour mixture. Mix on low speed for 1-2 minutes or until the texture begins to look like coarse sand
6. Add ⅓ of your wet ingredients into your flour mixture and mix on medium speed for 2 minutes. Make sure to stop and scrape the bowl in between.
7. While mixing on low, stream in the rest of your milk mixture and then increase the speed to medium speed and mix until combined. 
8.  Divide your batter evenly into your cake pans. PRO TIP: You can use a scale to divide your cake batter evenly between the cake pans for even layers!
9. Bake the cake layers for about 35-40 minutes or until a toothpick comes out clean from the center. If you are making a larger cake with more batter then the cake will take longer to bake.
10. Allow your cakes to cool in the pans until the pans are barely warm to the touch before flipping them out onto a cooling rack to cool fully. I like to put my cake layers into the freezer to cool down faster so I can decorate right away. This takes about an hour. You do not need to wrap your cakes in plastic wrap unless you are freezing them overnight.

Making The Graham Cracker Crumble

1. Add your crushed graham crackers and melted butter into a large bowl and mix with a spatula to combine. 
2. Place the crumble onto a baking sheet and bake it in the oven for 6-8 minutes. 
3. Let it cool down to room temperature and set it aside. We will use this for our crunchy filling and toppings.

Making The Toasted Marshmallow Frosting

1. Place the marshmallow fluff on a baking sheet and spread it as thin and as even as you can with a spatula (this helps toast the maximum amount of fluff).
2. Turn your oven on broil and place the sheet in the oven for about 2-5 minutes depending on how hot your oven is and how much you want it toasted. (Keep an eye on it and watch until it gets a dark golden brown color, then take it out.)
3. Once your marshmallow fluff is toasted, let it cool for 2-5 minutes until the pan is cool to the touch, then scrape it into your bowl of buttercream with a spatula (If the marshmallow is too warm, it will melt your buttercream). I'm using my easy buttercream recipe, but you can use any recipe that you like.
4. To make easy buttercream, place your egg whites, salt, and powdered sugar into the bowl of your stand mixer with the whisk attachment.
5. Mix on high for five minutes to dissolve the powdered sugar.
6. Add in your softened butter and vanilla extract. Continue mixing on high for 8-10 minutes or until the buttercream is light and fluffy and no longer tastes like butter.
7. Add in your toasted marshmallow fluff and mix until combined.
8. Switch to the paddle attachment and mix on low for 5-10 minutes to remove air bubbles.

Making The Hershey's Chocolate Ganache

1. Place your Hershey's Chocolate in a medium bowl and place it in the Microwave for about 15 seconds to soften it.
2. Heat your cream in the microwave in 30-second increments until it's very warm.
3. Pour your hot cream onto the chocolate and leave it to melt for about one minute.
4. Whisk the cream and chocolate together with a whisk until they are combined smoothly. Set it aside until you are ready to use it.

Assembling The S'mores Cake

1. OPTIONAL: Trim the brown edges off your cakes and the top dome so you get a cleaner look when slicing. 
2. Place your first cake layer on a cake board matching the size of your cake.
3. Place a layer of chocolate ganache onto your first layer of cake and smooth it with an offset spatula.
4. Add a scoop of marshmallow buttercream on top of the ganache and spread it out evenly.
5. Then sprinkle a layer of graham cracker crust on top of the buttercream.
6. Place your second layer of cake on top and repeat the process. 
7. Place your third cake layer on top and create a crumb coat by smoothing a thin layer of marshmallow buttercream all around the cake. Place in the fridge for 15-30 minutes until the cake is firm to the touch.
8. Apply a final coat of buttercream to the sides of the cake and smooth it with a bench scraper and offset spatula. Do the same thing to the top. Place the cake in the fridge to set the buttercream before doing your final decoration.

Decorating The S'mores Cake

1. The ganache drip works best at about 90ºF. If yours is hot, make sure you let it cool down before you use it. If yours is too cold, re-warm it in the microwave until it's about 90ºF.
2. Fill a piping bag with the ganache and pipe it onto the edges of the chilled cake, letting it drip down the sides.
3. Use the leftovers to fill in the center and smooth it out with a spoon or offset spatula.
4. Pick up your cake from the bottom and spread the graham cracker crust all over the bottom rim of your cake. PRO TIP: Have a baking sheet or parchment underneath to catch the escapees.
5. Top with toasted marshmallows and more graham cracker crust crumbles.
6. This can be served right away or made a few days ahead. It will hold up n the fridge for about a week, and about a month in the freezer, but I would add the marshmallow decor the day of so they don't become stale. 

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