Instructions

Cake preparation

1. Preheat oven to 350 degrees. Spray two 8"-inch round cake pans with cooking spray and line the bottoms with parchment paper. Set aside.
2. In the bowl of a stand mixer, cream together the butter and sugar until light and fluffy. Add eggs one at a time, beating well after each addition.
3. Sift the flour, cocoa, baking soda, and salt together and add alternately with the buttermilk and vanilla, beating well after each addition. Add the boiling water and mix well, scraping the sides of the bowl as needed, then pour into the prepared cake pans and bake for 30 minutes at 350 degrees or until a toothpick inserted into the center of the cake comes out clean. Remove from pans and cool completely on baking racks.

Frosting preparation

1. In a medium saucepan, whisk together the flour, salt and milk over medium-high heat and cook until it thickens to form a roux or thick sort of pudding almost, then remove from heat and allow to cool completely, stirring while it cools.
2. Once the roux is completely cool, cream the butter and sugar together in a separate bowl for 2-4 minutes, until light and fluffy, then add the vanilla. Then, while beating, add in the cooled flour/milk mixture and beat well until the frosting is smooth and creamy.

Assembly

1. To assemble the Black Forest cake, first level off any dome so that each layer of the cake is nice and flat, then slice each cake horizontally into two layers so that there are four evenly sized cake rounds.
2. Set the first cake layer on a serving plate or cake stand, then cover with 1/3 of the cherry pie filling. Gently lay the next cake round on top of the cherries and spread with about 1/2 of the ermine buttercream to create a nice layer of frosting (I don't always use the entire batch of frosting so it might be a little less than half).
3. Add the third layer of cake on top of the buttercream and top it with 1/3 of the remaining cherries. Add the fourth cake layer and cover it with the remaining frosting, then top with remaining cherry pie filling in the center without going all the way to the edges of the cake. Do not frost sides of cake.
4. Let the cake sit for 8-12 hours or more for the chocolate cake layers to absorb some of the cherry filling, then slice and serve.