Cream butter and sugar together, add eggs, one at a time, and vanilla.
Sift flour, cocoa and baking powder together and add to creamed mixture.
Bake for 50 minutes at 250º.
While still hot, add spoonfulls of marshmallow cream on top of hot cake, can place back in oven for a few minutes while marshmallow cream melts, spread warm marshmallow cream evenly and let cool.
Cake must cool completely before icing.
Top cake with chocolate icing.
Cook above ingredients on medium heat, bring to boil for 3 minutes, and remove from heat. Add 1/2 tsp. vanilla and stir with whisk until smooth, pour quickly over cake.