01 -
Heat your oven to 350°F. Grease a 9x5-inch loaf pan and set it aside.
02 -
Whisk together flour, cocoa powder, baking soda, and salt in a bowl. Set aside.
03 -
Beat butter and sugar with an electric mixer until light and fluffy, about 3-4 minutes.
04 -
Beat in eggs one at a time, then vanilla. Mix well after each addition.
05 -
Alternately add dry ingredients and buttermilk to the butter mixture, starting and ending with dry ingredients. Fold in hot fudge sauce gently.
06 -
Pour into prepared pan and bake 50-60 minutes until a toothpick comes out clean. Cool 10 minutes in pan, then remove to wire rack. Drizzle with extra hot fudge if desired.