Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round baking pans.

In a large bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.

Add buttermilk, vegetable oil, eggs, and vanilla extract. Beat on medium speed until smooth and well combined.

Stir in boiling water carefully (the batter will be thin). Divide the batter evenly between the two prepared pans.

Bake for 30-35 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then transfer them to wire racks to cool completely.

Make the Chocolate Ganache:

In a small saucepan, heat the heavy cream until it just begins to boil.

Pour the hot cream over the chocolate chips in a heatproof bowl. Let it sit for 2-3 minutes, then stir until smooth and glossy.

Place one cake layer on a serving plate. Spread a generous layer of ganache over the top and sprinkle half of the chopped candy bars.

Place the second cake layer on top. Pour the remaining ganache over the entire cake, allowing it to drip down the sides.

Sprinkle the remaining chopped candy bars on top of the cake for a final touch of indulgence.

For even more chocolate overload, add a layer of chocolate fudge between the cake layers before spreading the ganache!