Preheat the oven to 350°F.
Grease 3, 9-in. springform cake pans.
In a bowl, combine the dry ingredients: flour, granulated sugar, cocoa powder, espresso powder, baking soda, baking powder, and salt.
In the bowl of a stand mixer, beat to combine the eggs, buttermilk, 1 ½ cups room temperature water, vegetable oil, and vanilla extract. Beat until smooth and combined.
Divide the batter evenly among the three greased springform pans.
Place the cake pans in the oven and bake for 15 minutes, then rotate and bake for an additional 15 mintues. If a toothpick inserted in the center comes out wet after 30 minutes of baking, bake an additonal 2-3 minutes.
When finished baking, remove from the oven and allow the cakes to cool in the pans for 15 minutes. Remove from the pans and place the cakes on a wire rack to finish cooling to room temperature.
While the cakes bake, prepare the ganache: Place the semi-sweet chocolate in a heat proof bowl. Warm the heavy cream on the stovetop or in the microwave until just barely steaming, not boiling. Pour the hot cream over the chocolate. Allow to sit for 2 minutes to melt the chocolate, then whisk until smooth.
Allow the cakes and ganache to cool completely, about 2 hours.
When the cakes and ganache have cooled, assemble the cake. Use a few tablespoons of ganache between each layer, as well as to frost the top and sides of the finished layer cake.
Drizzle the cake with the cooled Bourbon Pecan Caramel and serve.