Here is a chocolate cake recipe that gives you a three layer cake with marshmallow filling and a milk chocolate ganache drizzled over the top while it is still warm.
Preheat oven to 350°F.
Prepare three 9-inch cake pans by lining with parchment paper, greasing and lightly flouring.
Put 2 cups of water into a saucepan, mix in the cocoa and boil. Stir until combined and smooth, then turn off and set aside to cool.
In a bowl, mix together the flour, sugar, baking soda, baking powder and salt.
In a large bowl, use an electric mixer to beat the butter, sugar, eggs and vanilla together.
Beat in the the dry ingredients alternating with the chocolate mixture.
Beat just until blended, do not over mix.
Divide the batter into the three prepared pans and bake for about 30 minutes or until a toothpick inserted in the middle comes out clean.
Remove cakes from oven, place on cooling racks and leave them in the pans for 5 minutes.
After 5 minutes, remove from pans, remove the parchment paper and cool completely on wire racks before frosting.
Let the cakes cool completely before frosting.
Cream together butter and the sugar until light and fluffy. Add vanilla, marshmallow and enough milk to make a fluffy filling. Beat until well blended.
In a double boiler or a pot filled with water and a bowl, melt chocolate, butter and heavy cream. Stir until smooth.
Place a layer of cake, then a layer of marshmallow filling, a second layer of cake with the remaining marshmallow filling.
Place the top layer of cake and drizzle on the ganache, letting it run down the sides. Let the ganache cool for an hour before cutting the cake.