Preheat oven to 350°F and grease a standard bundt pan.
Mix together eggs, sour cream, oil, coffee, and rum until smooth.
Slowly mix cake and pudding mix into the wet ingredients, then fold in chocolate chips.
Transfer batter to the prepared bundt pan and bake for 50-55 minutes.
Allow cake to cool, then prepare the ganache.
Ganache: Heat heavy cream in the microwave or on the stovetop. Add the chopped chocolate to a small bowl and pour warmed cream over top. Let sit 1 minute, then stir until smooth.
Invert the cooled cake onto a plate or serving dish of your choice, then drizzle ganache over top.