⅓ cup coconut oil (at room temperature) or oil of choice (I use coconut oil). Note: Oil yields a moister cake than butter
⅓ cup natural, unsweetened peanut butter
1 cup brown sugar
2 large eggs
1 cup buttermilk
1 teaspoon vanilla extract
Preheat the oven to 350 degrees F.
In a medium bowl, sift the flour, baking powder, baking soda and salt. Set aside.
In a large mixing bowl, add the peanut butter, oil, and brown sugar. Beat until combined and creamy. Add the eggs and vanilla extract and beat just until combined.
Alternately add the flour and buttermilk to the wet mixture, beating just until combined. Be careful not to over-beat or the cake will be dense and dry. A few small lumps of flour is fine.
Grease a 9X3 inch round baking pan (I use Magic Line pans)
Pour the batter into the pan.
Bake for about 30 minutes or until a toothpick inserted into the middle of the cake comes out moist (not wet with batter but moist. If the toothpick is dry, the cake is over-baked and will be dry).
Let the cake sit in the pan for 5 minutes, then invert the cake onto a wire rack to cool completely.
In the meantime, to make the frosting, place the peanut butter and butter in a large mixing bowl. Beat until smooth and creamy. Add the powdered sugar one cup at a time, continuing to beat. Add the heavy cream until you reach a spreadable consistency. (Note: This is a fairly stiff frosting)
Cut the cooled cake in half horizontally. Frost the bottom half of the cake and down the sides. Place the top layer of the cake, upside down, on top of the bottom layer. Frost the top layer and down the sides.
To cut back on calories (and save yourself some work), bake the cake in a 9X13 cake pan as a sheet cake and make half the amount of frosting to go on top. Also, for a more moist and goopey version, prepare the sheet cake. In a small saucepan bring ¼ cup honey, ¼ cup brown sugar and 2 tablespoons of butter to a boil. Remove from heat. Poke some holes throughout the sheet cake and drizzle the honey glaze evenly over it. Allow to cool completely and then frost (remember, half the recipe amount for the frosting). Note, I haven't actually tried this version, merely conceptualized it in my mind, but I think it would work ;) Note: For chocolate frosting, add a couple of tablespoons of good quality cocoa powder.
*Variation: Add Nutella to the frosting
*Another variation: Pour some chocolate ganache over it for ultra decadence!