For the cake: Preheat the oven to 350 degrees F. Grease two 9-inch bunt cake pans with butter and then dust with flour, tapping out the excess.
Place the softened butter and sugar in the bowl of a stand mixer fitted with the paddle attachment. Mix on low speed just until the ingredients are blended together, a few seconds, then raise the speed to medium-low and continue to mix until smooth, about 1 additional minute. Scrape down the sides of the bowl.
Combine the espresso powder and water in a small bowl.
With the motor running, pour in the espresso. Then add the eggs, 1 at a time, adding the next one after the previous one has been absorbed into the mixture. Stop the motor periodically and scrape the bowl from the bottom with a rubber spatula to integrate the ingredients and return the mixer to medium-low speed.
After all the eggs are added, continue to mix for an additional minute to ensure the eggs have been thoroughly mixed in.
While the mixture fully incorporates, combine the cocoa powder, baking soda, salt and baking powder in a medium bowl.
With the motor running, add half the buttermilk and all the black food coloring. Stop the motor to scrape the sides and bottom. Mix in half of the dry ingredients, stop and scrape the bowl, add the rest of your buttermilk and finish by adding the remaining dry ingredients. Continue to mix just until all ingredients are completely combined but do not over mix the mixture or it will result in a chewy dry cake.
Scrape the batter into the prepared pans with a rubber spatula to scrape down the bowl and get as much of the batter out as possible. Bake until the cake begins to pull from the sides of the pan and is springy to the touch, 25 to 30 minutes.
Remove the cakes from the oven and let cool for 10 minutes before flipping out onto your serving platter.
For the ganache: Place the heavy cream into a small saucepan over high heat and allow to come to a boil.
Put the chocolate, raspberry puree and food coloring into a large glass bowl.
Once the cream reaches a boil, pour over the chocolate and allow the cream to melt the chocolate. Stir to combine.
Place the berries into the center of the cake. Pour the warm ganache into center of the cake and over the edges.