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

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

In a separate bowl, combine the buttermilk, vegetable oil, eggs, and vanilla extract. Whisk until smooth.

Gradually mix the wet ingredients into the dry ingredients until just combined.

Stir in the boiling water until the batter is glossy and smooth.

Divide the batter evenly between the prepared cake pans and bake for 30-35 minutes.

Let the cakes cool in the pans for about 10 minutes before transferring them to a wire rack.

In a bowl, combine powdered sugar, cocoa powder, butter, heavy cream, and chocolate syrup. Mix until creamy and spreadable.

Apply the frosting to the cooled cakes, layering them as desired.