This single-layer double chocolate cake recipe brings all the flavor of a mile-high fudge cake, but without all the extra fuss.
Preheat your oven to 350 degrees Fahrenheit. Whisk together the flour, brown sugar, cocoa powder, baking soda, baking powder, and salt in a mixing bowl.
In a separate bowl whisk together the buttermilk, oil and egg until smooth. Pour the wet ingredients into the dry and mix until fully incorporated.
Pour batter into a greased 8-inch cake pan and bake for 30-35 minutes.
Allow it to cool for about 5-10 minutes in the pan before inverting onto a cooling rack and allowing it to cool completely.
In a mixing bowl, beat the butter on medium speed until smooth.