01 -
Set your oven to 350°F and grease a 9x5 pan with butter or baking spray.
02 -
In a bowl, whisk the cocoa, flour, soda, and salt until smooth and combined.
03 -
Cream the butter and sugar until light and airy. Add eggs one by one, then mix in the vanilla.
04 -
Alternate adding dry mixture and buttermilk, beginning and finishing with dry. Gently fold in the heated fudge sauce at the end.
05 -
Pour batter into the pan, level the top, and bake for 50-60 minutes. Let it cool in the pan for about 10 minutes, then take it out.
06 -
Once completely cool on a rack, top with the leftover warm fudge sauce.