Instructions

1. Peanut butter cake
   Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced. Grease and line a quarter sheet pan with baking or parchment paper.
2. 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.
3. Next, add eggs, one at a time. Beat on a low speed to combine. Don’t worry if the mixture looks curdled – this is normal.
4. Add baking powder, salt 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.
5. Pour batter into prepare pan and bake for approximately 35-40 minutes or until cake is golden brown and a skewer inserted in the middle comes out clean. Leave in pan to cool completely.
6. Chocolate buttercream
   To make the frosting, place butter in a large mixing bowl and beat with an electric mixer on medium speed for a couple of minutes until pale and creamy. Meanwhile melt the chocolate in a microwave, stirring in between 20 second bursts, until just melted and set aside to cool a little.
7. Once the butter is very pale and creamy, add half the sugar and one tablespoon of milk and beat on low until the sugar is incorporated. Then, add the rest of the sugar and another tablespoon of milk, and again beat on slow until the sugar is incorporated before turning up to medium for another minute or so.
8. Next, add melted chocolate to the buttercream, ensuring the chocolate is still smooth and melted but is not warm. Add peanut butter. Beat until the chocolate and peanut butter is completely mixed through. If the frosting is a bit thick, add an extra tablespoon of milk.
9. Generously spread the chocolate frosting all over the cooled peanut butter cake. Scatter over mini M&M’s.