Preheat oven to 350°.
Prepare two 9-inch cake pans. Spray with nonstick spray and coat with cocoa powder.
In a saucepan, melt butter and cocoa powder.
Once boiled,, turn off heat and add sugars. Both white and brown stir until combined. Let cool. Don’t worry if it is gritty at this point, because once you mix everything it will be glossy and not gritty.
Add the chocolate to a bowl. Slowly add each egg one at a time, mixing the batter before adding the next egg.
Add the vanilla to the buttermilk.
Alternatively, add the dry ingredients and the buttermilk to the chocolate mixture. Make sure to start and end with the dry ingredients. Make sure to scrape down the sides of the bowl between each addition of ingredients.
Once all ingredients are together, mix for about 1 minute on medium speed.
Pour your batter out equally into your prepared cake pans. I use an ice cream scoop and now that I need 5 ½ scoops of batter equally.
Bake at 350° for 30-35 minutes or when poked with a toothpick it comes out clean
Let cool in the pan for 30 minutes.
Take it out of the pan, and let it cool for about 1 to 2 hours at room temperature.
If not frosting right away, wrap it with plastic wrap and foil.