Ingredients
For the Chocolate Cake
- 2 cups all-purpose flour
- 2 cups granulated sugar
- ¾ cup unsweetened cocoa powder
- 2 tsp baking powder
- 1½ tsp baking soda
- 1 tsp salt
- 2 large eggs
- 1 cup buttermilk
- ½ cup vegetable oil
- 2 tsp vanilla extract
- 1 cup hot coffee (or hot water)
Rocky Road Filling
- 2 cups mini marshmallows
- 1 cup chopped toasted walnuts (or pecans)
- ½ cup semi-sweet chocolate chips
Chocolate Frosting
- 1 cup (2 sticks) unsalted butter, softened
- ¾ cup unsweetened cocoa powder
- 4 cups powdered sugar
- ¼ cup heavy cream (plus more if needed)
- 2 tsp vanilla extract
- Pinch of salt
Optional Toppings
- Extra mini marshmallows
- Chocolate drizzle
- Chopped walnuts
- Chocolate curls
Instructions
1. Prepare the Cake Batter
Preheat the oven to 350°F . Grease and line two 9-inch round cake pans. Whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Add the eggs, buttermilk, oil, and vanilla, then mix until smooth. Slowly stir in the hot coffee until fully incorporated. The batter will be thin.
2. Bake the Cake Layers
Divide the batter evenly between the prepared pans. Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean. Cool for 10 minutes before transferring the cakes to a wire rack to cool completely.
3. Make the Chocolate Frosting
Beat the softened butter until creamy. Mix in the cocoa powder, then gradually add the powdered sugar, alternating with the heavy cream. Stir in the vanilla and salt, beating until light and fluffy.
4. Build the Rocky Road Filling
Spread a layer of chocolate frosting over one cooled cake layer. Sprinkle evenly with the mini marshmallows, chopped walnuts, and chocolate chips. Gently press them into the frosting before placing the second cake layer on top.
5. Frost the Cake
Cover the top and sides of the cake with the remaining chocolate frosting. Smooth the frosting with an offset spatula or create decorative swirls.
6. Decorate with Rocky Road Toppings
Pile extra mini marshmallows around the top edge, sprinkle with chopped walnuts, and drizzle with melted chocolate. Add chocolate curls for an extra bakery-style finish if desired.
7. Slice and Enjoy
Allow the cake to sit for about 20 minutes before slicing. Serve at room temperature for the softest frosting and the gooey marshmallow texture.