Heat the oven to 350F. Grease and flour an 8inch cake pan.

In a large bowl mix all the dry ingredients together. In another bowl whisk all the wet ingredients together. Add the wet ingredients to the dry ingredients and fold in until just combined.
Pour the batter into the cake pan and bake for 35mins or until a toothpick into the middle comes out clean. Allow to cool for 15mins and then transfer to a cooling rack. Let cool completely before frosting.

Frosting
Beat butter, cream cheese and peanut butter with an electric whisk on medium till light and fluffy.
Add the icing sugar about half a cup at a time, mixing on low until fully mixed in. Turn up to medium high and beat till light and fluffy.

To assemble
Spread a thick layer of pb frosting all over the top of the cake swirling as you go. Enjoy!