Rocky Road Cake

5 from 1 vote

Rich, dark chocolate cake layers, filled with chocolate ganache, marshmallows, peanuts and toffee bits, covered with a silky chocolate buttercream.

Course: Dessert

Cuisine: Cake

Keyword: chocolate buttercream, Chocolate Cake, Rocky Road, Rocky Road Cake

2 cups (452 g) unsalted butter, slightly cold
10 oz. good quality chocolate of your choice, I use dark or semi, melted and cooled
5 cups (625 g) powdered sugar, measured and then sifted
2 teaspoons (8.4 g) pure vanilla extract
Pinch of salt
1/4 cup (57.7 g) heavy cream
*This buttercream recipe makes enough to fill and cover your cake. If you want to add additional piping you’ll want to make an extra 1/4 batch.

Preheat the oven to 325 degrees F. Spray three 8-inch round cake pans with nonstick spray. Line the bottom of each pan with parchment paper, then spray the parchment paper. Set aside.
In a medium size mixing bowl, whisk together the flour, sugar, cocoa, baking soda, baking powder, and salt. Set aside.
In another bowl, combine the buttermilk, oil, eggs, water (or coffee) and vanilla. Whisk until combined.
With the mixer on low speed, slowly add the wet ingredients to the dry, scraping the bottom of the bowl with a rubber spatula.
Evenly divide the batter into each of the three pans (about 15 to 16 ounces of batter in each 8-inch pan). Bake for 23 to 28 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs on it.
Cool in the pans for 10 minutes, then turn them out onto a cooling rack and cool completely. (I like to spray my cooling racks with nonstick spray to ensure non of the cake sticks to the racks).
If needed, level your cake layers to ensure a completely even surface for frosting and stacking. After leveling you can wrap each cake layer in plastic wrap and freeze until ready to use.

Heat the cream in a microwave safe bowl for about one to two minutes. Pour the heated cream over the chocolate chips in a medium sized bowl. Let sit for about five minutes.
Stir the chocolate and cream until nice and smooth. Add the marshmallows, peanuts and toffee bits and stir until combined.
Let the filling cool before using.
If you make the filling ahead of time, you will want to heat it up slightly to make it spreadable again.

In a microwave safe bowl, heat the chocolate chips and heavy cream for about 40 to 60 seconds. Stir until smooth. Let cool slightly.
In a bowl fitted with a paddle attachment, beat the butter on medium speed for about two minutes.
With the mixer on low speed, slowly add the chocolate ganache and stir until smooth. Gradually add the powdered sugar and mix until combined.
Add the vanilla and salt. Turn the mixer to medium-high and beat the buttercream for another 3-4 minutes until light and fluffy.
Before frosting your cake, use a wooden spoon to hand mix the frosting to push out air bubbles.

Place the first cake layer on a cake board or cake plate, top side up.
Pipe a rim of frosting around the edge of cake layer before adding the filling. This creates a nice barrier so the filling stays in place.
Spread half of the filling within the frosting barrier.
Place the second cake layer on top and repeat steps 2 and 3.
Place your final cake layer, top side down, on top of the filling. Spread a thin layer of buttercream around the entire cake. This is the crumb coat and will help lock crumbs into place. Freeze for about 10 minutes to set the crumb coat.
Continue to frost the cake with the remainder of the chocolate buttercream, saving about a half cup of buttercream to do the design show above.