For the cake
1 cup unsalted butter, room temperature
1 cup brown sugar
½ cup caster sugar
1 cup smooth peanut butter, room temperature
1 tsp vanilla extract
3 large eggs, room temperature
1½ tsp baking powder
2 cups self-raising flour
For the peanut butter cream cheese frosting
250g cream cheese, room temperature
150g unsalted butter, room temperature
150g smooth peanut butter
1 tsp vanilla extract
500g icing sugar
3 tbsp milk
Preheat oven to 160C and line a round tin with baking paper.
Place butter and sugars in a large mixing bowl. Beat together with an electric mixer on medium speed until pale and creamy. Add peanut butter and vanilla and mix together until smooth and combined.
Add eggs, one at a time.
Beat on a low speed to combine. Don’t worry if the mixture looks curdled – this is normal.
Add baking powder and half of the flour, followed by all of the milk. Beat on a low speed to combine, then add the final half of flour. The cake batter should be thick and smooth.
Pour batter into prepare pan and bake for approximately 25-30 minutes or until cake is golden brown and a skewer inserted in the middle comes out clean. Leave in the pan to cool completely.
To make the cream cheese frosting, add butter and cream cheese to a large mixing bowl. Beat with an electric mixer for 2-3 minutes until smooth and creamy. Add peanut butter and vanilla and beat briefly. Then, add sugar, 1 cup at a time, along with 2 tablespoons of milk, and continue to beat until smooth. If the frosting is too thick, add an extra tablespoon of milk.
Gently remove cooled cake from pan and remove the baking paper. Cut out three 6-inch layers using a 6-inch cake ring. Place a 6-inch cake ring on a cake board or plate. Line the inside of the cake ring with a sheet of acetate. Place two half pieces of cake at the bottom. Press down the cake firmly. If there are any gaps, use extra cake scraps to fill in the holes and press down very firmly to make one even layer. Next, add a thin layer of cream cheese frosting.
Add another layer of peanut butter cake on top and press down firmly. Add more cream cheese frosting on top. Place cake in the fridge for at least 2 hours to set. Cut and serve.