Preheat oven to 350 degrees. Line two 8-inch pans with parchment paper rounds and spray with non-stick spray or grease with Crisco. (NOTE: You can use three 6-inch pans if you'd like)
Combine the sugar and butter in the bowl of a stand mixer and blend for 1 minute.
Add in the eggs, one by one. Add baking powder, baking soda and salt. Mix for one minute.
In a separate bowl, add cup of hot water (not boiling), cup of buttermilk and cup of dark cocoa and whisk until mixture is smooth. Set aside.
Add 1 cup of flour into the butter/sugar/egg mixture. Mix until flour is completely incorporated.
Add the buttermilk/cocoa mixture into the flour mixture and gently mix until completely combined. Do this slowly or it will make a mess.
Add 2nd cup of flour and mix at low speed until flour is mixed in.
Divide the batter evenly between your prepared pans
Bake for 35-40 minutes or until toothpick comes out clean.
Set layers aside to cool for 10 minutes. Remove layers from pans and freeze cake layers for about 45 minutes while you make the buttercream frosting and ganache.