2Grease two 8-by-2-inch round cake pans; line bottoms with parchment. Dust pans with cocoa powder.
3Stir together sugar, flour, cocoa, baking powder, baking soda and salt in large bowl. Add eggs, milk, oil and vanilla. Beat on medium speed with an electric mixer for 2 minutes.
4Stir in boiling water. Note: Don’t worry the batter is supposed to be thin
5Pour batter into prepared pans and bake in the preheated oven for 30 to 35 minutes. You will know they are done when a wooden toothpick inserted into the cake comes out clean.
6Let the cakes cool for 10 minutes and then transfer to a wire cooling rack to cool completely.
7Remove the parchment paper from the cool cakes. Using a long serrated knife carefully cut each cake in half to create four layers. Reserve any crumbs to sprinkle over the iced cake.
8Place the first layer onto your cake plate and spread about 1 1/2 cups over the top. Continuing doing this for the remaining layers. There is no need to cover the outside of the cake.
9Tip: To keep the frosting off of your finished cake plate place two sheets of wax paper onto the plate and let them slightly overlap each other. When you are finished icing the cake you can gently remove the wax paper.
For The Frosting
1Whip butter and powdered sugar with an electric mixer until no lumps remain.
2Add marshmallow fluff and mix until blended.
3Add vanilla, salt and milk, mix until light and fluffy, about 2?3 minutes.