Preheat the oven to 350º F.

In a large mixing bowl combine the buttermilk, melted butter, eggs, vanilla extract, devil’s food cake mix, sugar, flour, and cocoa powder, beat with an electric mixer until combined, 1-2 minutes.

Spray a 9x13 inch pan with non-stick cooking spray. Pour the batter into the pan and bake for 30-32 minutes or until a toothpick inserted in the center of the cake comes out clean. Allow the cake to cool completely before adding frosting.

Place room temperature unsalted butter in a mixing bowl. Use an electric mixer on medium and beat the butter for 1 minute, until whipped and fluffy. 

Add in the cocoa powder, powdered sugar and vanilla extract, beat again on low for 1-2 minutes, scraping down the sides of the bowl, until everything is incorporated. 

If the frosting is too thick, add a tablespoon of milk or heavy cream, and beat until creamy. 

Spread on top of the cooled cake, add chocolate curls if desired. My secret for making easy chocolate curls is to get a hershey’s bar and use a vegetable peeler to make curls, it’s so simple! Be sure to hold the chocolate bar on the wrapper so the heat from your fingers doesn’t leave imprints on the chocolate bar.