Preheat oven to 350 degrees F and generously grease a bundt pan with non stick cooking spray and flour.
In a medium bowl, whisk the flour, baking soda, cocoa powder, and sugar together until well combined. Set aside.
In a large mixing bowl, whisk together the eggs, buttermilk, sour cream, melted butter, oil, and vanilla extract.
Add the dry ingredients to the wet chocolate mixture and whisk together just until combined. You could also use an electric hand mixer but a whisk works too.
Slowly stream in the hot water and mix until smooth and evenly incorporated into the cake batter. Be sure to scrape the sides of the bowl with a rubber spatula.
Pour the cake batter into the prepared bundt pan and place in the center rack in the oven, bake for 45-55 minutes or toothpick inserted into the center of the cake comes out clean. Allow the cake to cool in the pan, set on a wire rack, for 10 minutes. Then flip the cake onto the cooling rack and cool completely.