Preheat oven to 350℉. Prepare a bundt pan by generously coating with 3 tablespoons of softened butter, then coat with cocoa powder. Set aside.
In a medium-sized bowl, whisk together flour, sugar, baking soda, salt, and instant espresso powder. Set aside.
In a large bowl, whisk together the eggs, buttermilk, and vanilla extract. Set Aside.
Add butter to a medium-sized pot. Melt over medium heat. Once melted, add oil, cocoa powder, and iced coffee. While whisking constantly, bring to a boil. Remove from heat.
Alternate adding the dry ingredients and hot butter mixture into the buttermilk mixture in 3 parts, starting and ending with the dry ingredients. Mixing after each addition.
Pour batter into prepared bundt pan. Bake for 45-50 minutes, until a cake tester inserted comes out with a few moist crumbs.
Cool cake in pan for 5 minutes, then invert and cool on a wire rack to cool completely.
Espresso Ganache
While cake is cooling, add heavy cream and espresso powder to a microwave-safe container and heat until very hot but not boiling. Add chocolate chips to a medium-sized bowl.
Pour hot cream over chocolate chips and let sit for 5 minutes. Stir the chocolate mixture until shiny and smooth.
Use a large spoon to drizzle generously over the cooled cake. Enjoy!