Rocky Road Chocolate Cake
Rich, fluffy chocolate cake with chocolate marshmallow buttercream, mini marshmallows, chopped nuts, and chocolate ganache. This is a simple yet incredibly delicious cake version of the classic ice cream flavor!
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Why this recipe works
First, the chocolate cake. It’s just SO good. Fluffy yet moist, rich but not overly so, and the perfect amount of sweet. It’s my absolute favorite chocolate cake. It’s that white whale of cakes: fluffy and moist yet sturdy and reliable. It’s great for stacking nice and tall.
Then, the frosting. Oh my, how I love this frosting. It’s just so silky and flavorful. It’s a blend of marshmallow fluff, chocolate ganache, and buttercream. It’s basically a blend of my chocolate ganache buttercream and my marshmallow buttercream, and it’s sheer frosting perfection.
Added to this all is a filling of mini marshmallows, chopped walnuts (or nut of your choice), and a chocolate ganache drizzle. It may sound a little extra, but it’s not overly complicated and is worth every second it takes to create this rocky road cake.
Key ingredients
Flour. Be sure to spoon then level your flour so you don’t pack it in, and always sift with a fine mesh sieve!
Cocoa powder. Sifting this is a must, as it tends to clump. Be sure you use unsweetened cocoa. Regular is preferred, but Dutched will work as well.
Sugar. Obviously! You’ll need this in the cake as well as the caramel sauce.
Baking powder/soda. Both are needed to help the cake rise properly. Be sure they haven’t been open longer than a few months or they do start to lose their umph, regardless of the indicated expiration date. And be sure they’ve been well-sealed! Any moisture getting in will stop them from working properly.
Salt. Again, needed in all elements of this cake. I highly recommend sea salt, as it helps complement the sweetness better.
Buttermilk. I always make my own by adding 1 tablespoon white vinegar to a 1 cup measuring cup. I then fill it the rest of the way with room-temperature whole milk.
Oil. I prefer avocado or grape seed oil, as they are light and tasteless but still heart-healthy. Vegetable or canola oil work, too.
Eggs. Use fresh, large eggs and make sure they have reached room temperature.
Vanilla. Always use pure extract in baking, not imitation.
Hot coffee. Be sure your coffee is piping hot when you use it. You can make it as strong or light as you’d like. I prefer blond coffee in most cakes, but you really can’t taste it if you use a dark roast. It just serves to bring out a more intensely dark chocolate flavor.
Chocolate marshmallow buttercream. One of my favorites! This is what really makes this cake because it gives you both the chocolate and the marshmallow and it sooooo silky smooth and delicious. *Note: If you’re in high heat/humidity or will be traveling with the cake, I suggest you use the cocoa powder substitution mentioned in the frosting recipe and discussed further in the notes below.
Walnuts. You can sub almonds, peanuts, or any preferred nut. I went with walnuts because it’s what I had and is pretty common in rocky road fudge. However, the rocky road ice cream we always get has almonds and most recipes I found online have peanuts. So…it’s whatever you like.
Mini marshmallows. In a pinch you can chop up regular marshmallows.
Chocolate chips. This is for the ganache, which is important to help “glue” each layer of cake to the nuts and marshmallows right beneath it. Otherwise, it’ll be prone to slipping. Plus, you can’t go wrong with a little extra ganache!
Heavy cream. Also for the ganache. I personally recommend making a double batch when you make the frosting, use half in that and save the rest for assembling the cake.
How to make rocky road chocolate cake
Make the cake
1. Sift and whisk dry ingredients. Don’t skip the sifting! It’s key to making this cake nice and fluffy.
2. Whisk eggs, buttermilk, oil, and vanilla. Whisk very well to fully emulsify (blend) it all, especially the eggs and oil.
3. Slowly whisk hot coffee into wet ingredients. Whisk very quickly and pour slowly to avoid scrambling the eggs. If you do think you scrambled some, you can run it through your fine mesh sieve.
4. Slowly stir wet ingredients into the dry. Do this on low and immediately stop and scrape the bowl once everything is combined.
5. Beat on medium for exactly 2 minutes. Set a timer so you don’t under or over mix.
6. Bake. Bake until a toothpick or cake tester comes out with just some moist crumbs—not fully clean, as this can mean it’s over baked. Remember that it continues to bake a little when you take it out of the oven.
Assemble
7. Make the frosting and ganache. I suggest making a double batch of the ganache when you do this, saving half for the filling. This means just one less step. However, if you prefer precise measurements or plan to use cocoa powder instead of ganache in the frosting (*see note below), you will need to make the ganache for the filling separately.
8. Chop and toast walnuts. Toasting is optional, but I like the taste of toasted nuts. You just need to bake them for 5-10 minutes at 350F/175C until golden.
9. Fill and frost cake. As you frost each layer, top with walnuts, mini marshmallows, and a nice drizzle of ganache. Be sure to go in that order, as the ganache acts as almost a glue helping the next layer of cake not slide off the nuts and marshmallows.
10. Decorate as desired. I basically decorated mine with a fancy iteration of the filling, dripping some ganache and creating a ring of marshmallows and nuts.
Enjoy
Tips and FAQ’s for this recipe
Make a double batch of ganache for the buttercream
Okay, that sounded weird, but I couldn’t think of how else to say that you need ganache for the filling AND for the buttercream, so you might as well just make a double batch, use half in the frosting then save the rest for filling the cake. I’m all about what’s easy. Plus, the frosting is fairly forgiving. You can use a little more or a little less ganache in it, so don’t worry about dividing your batch perfectly in half (although using a scale is one way to achieve that!).
*Will this cake hold up in high heat or while traveling?
Yes, to a point. It won’t hold up well in high heat, high humidity, or a long car ride (due to bumps and such). But there’s an easy fix. The frosting recipe has directions for making it more sturdy by using cocoa powder instead of ganache. This helps it hold up much better in heat, humidity, or traveling. Another good option is to refrigerate it until serving (or leaving the house with it). I don’t recommend refrigerating it for more than a few hours though. If you need to make it a few days ahead and live in high heat, I suggest freezing it, as this will not dry out the cake the way refrigeration will.
Can I make this ahead of time?
Yes! I always split up my work for more complicated cakes. I like to make the frosting a few days in advance and keep it refrigerated. Just be sure it comes fully to room temperature before using. The cake layers as well can be made the night before and kept (well-covered) on the counter overnight, but only if you will be frosting the cake in the morning. Otherwise, it’s best to let the cakes cool completely then wrap them in a double layer of plastic wrap and freeze them. Just be sure to let them defrost jut enough to be able to cut any domed tops off—you want to avoid freezing cut cake layers. Finally, you can easily chop and toast (if desired) the nuts ahead and keep them in an airtight container.
Do I have to use coffee in the cake?
Probably. You could technically use just hot water, but I have never been a fan of how this cake tastes without coffee. Trust me, you will not taste the coffee if you use light roast. If you’re worried, you can make it half strength, which should be enough to bring out the chocolate flavor.
Measure dry ingredients carefully
Always spoon flour and cocoa into your measuring cup then level with the back of a knife or other straight edge. And be sure to sift with a fine mesh sieve so your cake is nice and fluffy.
Sift your dry ingredients
Usually, you don’t need to sift the dry ingredients unless it’s cake. However, I realized that every time I tried making brownies, my cocoa left little clumps that in turn caused me to over mix my batter. Instead, sifting the dry ingredients means you can simply fold them into the wet ingredients without over mixing, resulting in a tender, fudgy brownie that’s not dense.
Use room temperature ingredients
This is another baking must. Room temperature ingredients (when called for) are non-negotiable. I have seen the difference in cakes that are tough and don’t rise. Plan ahead and make sure your ingredients have had time to sit out.
Use quality cocoa
Since cocoa is the main flavor here, you want a good brand. Opt for something organic and fair trade, if possible, because this usually means it was produced in smaller batches and thus higher quality and is often fresher, too. Plus, the flavor of the high quality cocoa is always noticeable in the brownies. My go-to is Volupta, from Costco, but some other good options are Ghirardelli, Guittard, Scharffen Berger, Anthony’s, or even Hershey’s Special Dark in a pinch.
My tools
Here are my must-have tools I use for making this cake. Affiliate links provided.
Mesh sieve (because sifting is KEY for a fluffy cake)
All-rubber spatula (this makes scraping the bowl easier so the batter and frosting doesn’t get all over a wooden handle!)
Silicone liners for 8” cake (or for 6” cakes)
8” aluminum cake pans or 6” aluminum cake pans (I’ve found nonstick doesn’t bake as evenly)
Offset spatula (for frosting the cake)
Rocky Road Chocolate Cake
- prep time: 40-45 minutes
- bake time: 25-30 minutes
- total time: 1 hour, 15 minutes (plus cooling time)
servings: 12-16
Ingredients:
- 1 ⅔ cups (333g) granulated sugar
- 1 ⅔ cups (227g) flour, sifted
- ¾ cup (75g) unsweetened cocoa or cacao powder, sifted
- 2 teaspoons (8g) baking powder, sifted
- 1 teaspoon (5g) baking soda, sifted
- ½ teaspoon (3g) fine ground Himalayan sea salt (or 1 teaspoon table salt, but sea salt gives a better flavor)
- 2 large eggs, room temperature
- 1 cup (240g) buttermilk*, room temperature
- ½ cup (120g) avocado or olive oil
- 1 tablespoon (13g) pure vanilla extract
- 1 cup (240g) very hot coffee (light or dark roast is fine)
- one batch chocolate marshmallow buttercream
- 1 cup (115g) walnuts, chopped (or nut of your choice)
- 1-1 ½ cups (50-75g) mini marshmallows
- 4 ounces (⅔ cup or 113g) chocolate chips or chopped baking chocolate**
- 3 ounces (85g) heavy whipping cream**
Instructions:
- Preheat your oven to 325F/165C. Lightly grease and flour two 8” or 9” cake pans or three 6” cake pans (or use baking spray) and line the bottom with parchment paper or silicone baking mats. This is also a great time to set your coffee to percolate (unless using hot water or espresso and hot water, which is what I do).
- In the bowl of stand mixer (or large bowl), use a large fine mesh sieve to whisk together sugar, flour, cocoa, baking powder, baking soda, and salt, being sure to sift as instructed. I prefer using a hand whisk for this step as the whisk attachment doesn't always get the very bottom mixed in. Fit this to your stand mixer with the paddle attachment. You can also use a large mixing bowl with a hand mixer. * I also like to make my coffee at this time so it’s fresh and hot.
- In a separate bowl, whisk together eggs, buttermilk, oil, and vanilla.
- VERY slowly, pour coffee mixture into the egg mixture, whisking the eggs quickly and constantly to avoid scrambling them. Feel free to do it in increments if this is your first time.
- Turn mixer to low. Slowly pour wet ingredients into dry. It will clump up halfway through then settle into a liquid-y consistency. Immediately turn off mixer once all ingredients are combined then scrape down sides with a rubber spatula, making sure to get to the very bottom. Beat on medium for exactly 2 minutes. Do not overmix!
- Pour batter evenly into prepared pans. Gently tap pans on the counter a couple times to get some of the bubbles out.
- Bake for 20-25 minutes if using three pans or 15-18 minutes if using four pans, until a toothpick inserted in the middle comes out with some moist crumbs but no raw batter. Always check cakes a little early, as oven time can vary. If not using a convection oven, rotate cakes halfway through.
- Cool in pans 5-10 minutes then remove to a cooling rack until completely cooled.
- While the cakes cool, make the frosting. This can also be made ahead and kept refrigerated up to 2 weeks (well-sealed) or frozen up to 2 months. Let come to room temperature on the counter.
- Make the ganache**. Combine the chocolate chips and heavy cream in a heatproof bowl. Heat in a microwave at half power in 30 second increments (or over a double boiler) until 75% or so melted. Stir until fully melted and smooth. Let cool slightly.
- If desired, you can also toast the chopped walnuts. Place on a rimmed baking sheet and bake at 350F/175C for 5-10 minutes, until golden and fragrant. Let cool completely.
- When ready to assemble, trim any rounded tops off of the cake layers with a long serrated knife or cake leveler. If you only made two layers, carefully cut each layer in half to make room for more filling.
- Place your first layer of cake on your cake plate/platter/etc. Spread a layer of frosting on the bottom layer of cake. Sprinkle some mini marshmallows then walnuts. I’d say about ½ cup marshmallows and about ¼ to ⅓ cup nuts is perfect, depending on the size of cake pans you used.
- Drizzle with ganache. I used quite a bit, but you can use less. Just use enough to help “glue” the next layer of cake to the marshmallows and nuts.
- Continue stacking and filling each layer in this method until all layers of cake are stacked. Cover the cake in a crumb coat of frosting and refrigerate at least 20 minutes. If the cake is already shifting as you try to crumb coat it, you can refrigerate it for a few minutes to set the filling before adding the crumb coat.
- Frost cake to desired thickness. Top with ganache drip and a ring of marshmallows and walnuts (or decorate as desired).
Enjoy!
Seal leftover cake with a piece of plastic wrap placed right against the cut edges and “seal” it by pressing against the buttercream along the edge. Then core in another layer of plastic wrap or store in an airtight cake container.
*You can make your own buttermilk by adding 1 tablespoon of white vinegar to a 1 cup measuring cup then filling the rest of the way with room temperature whole milk. Stir and let sit 5-10 minutes.
**Alternatively, you can double the ganache for the buttercream, use half in that and save the rest for the filling.
