Heat oven to 350 degrees F or 325 degrees convection with the rack in center position. Butter or spray one bundt pan.
In a large bowl, or in the bowl of a stand mixer, whisk together the sugar, flour, baking soda, baking powder, salt, and cocoa. Add eggs, vanilla, vegetable oil, buttermilk, and coffee. Beat by hand or on medium speed for 2 minutes; batter will be thin. Pour into the prepared bundt pan.
Bake for 30 - 35 minutes or until a toothpick inserted into center comes out clean. Cool in the pan for 20 minutes, then invert cake onto a wire rack and cool completely before frosting.
In the bowl of a stand mixer, beat cream cheese and butter until smooth. Beat in vanilla extract. Gradually add the sifted confectioners sugar, beating until frosting is smooth and creamy, about 5 minutes.
I actually don't feel qualified to tell you how to do this - it is so likely that you will be better at this than I am. If you have frosting bags and tips and want to make it look like my failed attempt at a Nothing Bundt Cake, have at it :-). Otherwise, use an offset spatula to spread the frosting. A bundt cake might lend itself to more of a drizzly icing but we love the cream cheese frosting so I made it work!
Adapted closely from The Merry GourmetMerry Jennifer says you can make this one day ahead. Cover with cake dome and refrigerate overnight. Let cake stand at room temperature for 2 hours before serving.