Preheat the oven to 180° degrees. Line cake pans with parchment paper and grease with butter or nonstick cooking spray, set aside.
In a medium bowl, stir together the boiling water, coffee powder, and semi-sweet chocolate until chocolate has dissolved and mixture is smooth. Set aside to cool.
In a large mixing bowl, whisk together the flour, cocoa powder, sugar, baking soda, baking powder, and salt until combined.
In another bowl, whisk together the eggs, buttermilk, vegetable oil, and vanilla. Pour wet ingredients into the dry ingredients and stir until smooth. Add the cooled espresso-chocolate mixture, stirring until just combined.
Divide batter evenly among the three pans and bake in the oven for 31-33 minutes, or until a toothpick inserted in the center of the cake comes out with few crumbs attached. Remove from the oven and allow to cool completely.