Preheat oven to 350 degrees and prepare bundt cake pan by lightly dusting with cocoa powder and flour.
Mix flour, baking soda, salt, and sugar; then set aside.
Now mix together butter and cocoa powder with hot water.
Add both mixtures (butter and flour) and blend with an electric mixer until smooth.
Now add eggs, sour cream, and vanilla extract. Mix until uniform.
Pour finished mixture into the bundt cake pan prepared earlier.