Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch round cake pans.
In a large bowl, combine flour, sugar, cocoa, baking powder, baking soda, and salt. Add eggs, milk, oil, and vanilla; beat with an electric mixer on medium speed for 2 minutes. Stir in boiling water (batter will be thin). Pour into prepared pans.
Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean. Cool in pans for 10 minutes, then remove from pans and cool completely on wire racks.
Using a serrated knife, slice each cake horizontally into two layers. Place one layer on a serving plate and spread with cherry pie filling. Top with another layer and repeat with the remaining layers and cherry filling.
In a large bowl, beat heavy cream and confectioners' sugar with an electric mixer until stiff peaks form. Spread over top and sides of cake. Garnish with chocolate shavings and cherries.