Football Cake

Preheat oven to 350°. Line a 9" round cake pan with parchment and grease with cooking spray. In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt.  In another large bowl whisk together buttermilk, oil, eggs, and vanilla. Add dry ingredients and mix just until combined, then add boiling water.  Pour batter into prepared pan and bake until a toothpick inserted into the middle comes out clean, 35 to 40 minutes. Let cool for 10 minutes, then invert onto a wire rack and let cool completely.  Meanwhile, make buttercream: In a large bowl using a hand mixer, beat butter until smooth. Add powdered sugar and beat until no lumps remain. Add heavy cream, vanilla, and salt and beat until combined.  Reserve 1 cup of buttercream and set aside. To remaining buttercream add cocoa powder and beat until combined.  Assemble cake: Using a serrated knife, mark a line down center of cake. Cut 3/4" away from the mark on both sides, removing the center completely. Save for another use or eat now! Sandwich the two halves together by frosting the cut sides with chocolate buttercream and pushing together.  Frost outside of cake with chocolate frosting and smooth with an offset spatula.  Place white buttercream in a piping bag and pipe lines and laces on cake.