This recipe is super easy and includes a few shortcuts. I used a basic 'one bowl' chocolate cake recipe, a favorite of mine since I hate cleaning up for hours after baking. The buttercream is very sweet, but delicious. I decided on a buttercream but adding the marshmallow cream to a cooked 7-minute frosting works well, and can even be torched at the end for a toasted marshmallow taste.
3/4 cup unsweetened, dark cocoa powder
1 1/2 cups all-purpose flour
1 1/2 cups sugar
1 1/2 tsp baking soda
3/4 tsp baking powder
3/4 tsp salt
2 large eggs
3/4 cup warm water
3/4 cup buttermilk (i make my own using milk and vinegar)
3 tablespoons vegetable oil
1 tsp pure vanilla extract
Preheat oven to 350 degrees and line standard tins. Sift together cocoa powder, flour, sugar, baking soda, baking powder, and salt into a large bowl. Add eggs, warm water, buttermilk, oil, and vanilla, and mix until smooth. Scrape down the sides and bottom of bowl to assure batter is well mixed.
Divide batter evenly among cups, filling each about 3/4 full. Bake until tops dome, about 20-22 minutes.
3 sticks unsalted, room temp butter
1 7oz jar marshmallow cream or fluff
3 1/2 - 4 cups confectionery sugar
1 tsp vanilla extract
Begin whipping butter in a stand mixer until fluffy, about 3-4 minutes. Add jar of marshmallow cream and continue whipping. Gradually add in sugar until desired consistency is met for piping. Add vanilla and mix again until incorporated.