Preheat your oven to 350°F (175°C) and prepare two 9-inch round cake pans by greasing and flouring them.

In a large mixing bowl, combine the dry ingredients: all-purpose flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt.

Add the wet ingredients: eggs, buttermilk, vegetable oil, orange zest, and vanilla extract to the dry mixture. Mix until smooth.

Carefully stir in the boiling water until well combined.

Pour the batter evenly into the prepared pans and smooth the tops.

Bake for 25-30 minutes, checking for doneness with a toothpick.

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

Frost with chocolate ganache after the cakes have completely cooled.