In a mixing jug, add Water (1 cup) and Instant Espresso Powder (1 tablespoon). Allow powder to dissolve. Add Buttermilk (1 cup). Set aside.
In a mixing bowl, add Butter (1 cup), Granulated Sugar (1 1/2 cup), and Brown Sugar (1/2 cup). Mix together until smooth.
Add Large Egg (3) and Vanilla Extract (2 teaspoon). Mix until batter is smooth.
In a separate bowl, add All-Purpose Flour (2 cup), Unsweetened Cocoa Powder (3/4 cup), Baking Soda (1 teaspoon), Baking Powder (2 teaspoon), and Salt (1 teaspoon).
Add the dry ingredients and buttermilk coffee mixture into the wet ingredients a bit at a time. Mix together until smooth.
Transfer batter to a lightly greased 9 by 13-inch rectangular pan. Bake at 350 degrees F (180 degrees C) for 30-35 minutes.
In a mixing bowl, add Semi-Sweet Chocolate Chips (12 ounce) and heated Heavy Cream (1 1/2 cup). Allow to melt together for 2 minutes. Whisk until smooth. Place in fridge to thicken.
Pour chocolate ganache over the cooled cake.