Preheat the oven: Preheat your oven to 350°F (175°C). Grease and line the bottoms of three 8-inch round cake pans with parchment paper.
Prepare the dry ingredients: In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
Combine wet ingredients: Add the buttermilk, vegetable oil, eggs, and vanilla extract to the dry ingredients. Mix until smooth.
Incorporate hot water: Gradually pour in the hot water while mixing. The batter will be thin but glossy and well-combined.
Bake the cakes: Divide the batter evenly among the prepared pans and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean. Let the cakes cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.
Make the ganache: Heat the heavy cream in a small saucepan until it just begins to simmer. Remove from heat and pour over the chopped dark chocolate. Let sit for 2 minutes, then stir until smooth and glossy. Allow to cool slightly for easier spreading.
Assemble the cake: Place one cake layer on a serving plate. Spread a generous layer of cherry pie filling on top, followed by a drizzle of ganache. Repeat with the remaining layers.
Frost and garnish: Frost the entire cake with the remaining ganache, letting it drip down the sides for a rustic look. Decorate the top with maraschino cherries and any remaining cherry filling.
Serve and enjoy: Slice and serve this decadent treat with your favorite beverage!