In a medium bowl, whisk the flour, cocoa powder, baking powder, baking soda, sugar and salt. Set aside. In a large bowl, beat the eggs, buttermilk, melted butter, and vanilla extract for 1 minute, until well combined.
2 cups All-purpose flour, 3/4 cup Unsweetened cocoa powder, 1 1/4 tsp Baking powder, 1 1/4 tsp Baking soda, 1 3/4 cups Granulated sugar, 1/2 tsp Kosher salt, 2 large Eggs, 1 cup Whole buttermilk, 1/2 cup Unsalted butter, 2 tsp Vanilla extract