Preheat oven 325 degrees F. Grease and lightly flour a bundt pan.
In a medium bowl, whisk together flour, cocoa powder, baking soda, and salt. Set aside.
Using an electric mixer, cream together the butter and sugar until light and fluffy.
Add in sour cream.
Alternate adding the flour mixture and the eggs. Add a little flour mixture, mix, then add in an egg, mix, do this until all is combined. At this point, the batter will be very thick.
Add in a cup of hot water and be careful not to burn yourself The mixture may splash out, so at this point, I use a whisk. The cake batter will be thin, this is normal. Whisk the mixture until smooth.
Stir in the extract vanilla.
Pour into prepared bundt pan and bake at 325 degrees F. for 1 hour to 1 hour and 20 minutes, or until done and a cake tester comes out clean.
Carefully remove the cake from the oven and allow to cool in the pan on a rack for 20 minutes before removing. At this point, you can slice and enjoy as is, add the frosting of your choice, or chocolate ganache.
For a quick and easy chocolate ganache. Bring 1/2 cup of heavy cream to a boil and pour over 4 ounces of good quality dark chocolate, chopped or broken into 1/2-inch pieces. Wait 1 minute and stir until smooth and glossy.
Drizzle chocolate ganache onto the cake while it is still warm. Slice and serve. Store at room temperature in an airtight container up to for 5 days