Preheat your oven to 180°C/160°C Fan. Grease a 20cm brownie tin or small roasting tin with the butter foil then line the base with baking paper.

Measure 125g butter into a microwaveable bowl. Break in the chocolate then zap in the microwave in 30 second bursts, stirring in between each one, until melted and glossy. Set aside.

Boil the kettle.

In a large bowl, whisk the sugar, flour and bicarb together along with a big pinch of salt until well combined - you want to get rid of any sugar lumps.

Crack the eggs into the bowl and add the yogurt. Pour in the melted chocolate mixture and whisk everything together until you have a smooth batter then whisk in 50ml boiling water - our secret ingredient.

Pour the cake batter into your prepared tin. Bake in the centre of your oven for 25 minutes until a knife/skewer pricked in the centre of the cake comes out clean. Leave to cool completely in the tin.

Frosting time. Tip the remaining butter into a bowl (make sure the butter is super soft - If not microwave for 10 seconds), add the peanut butter, icing sugar and a big pinch of salt. Using some elbow grease; whisk to combine. Slather on top of the cooled cake and top with a handful of roughly chopped salted peanuts if you like.

Eat and enjoy. These cakes will keep in a container out of the fridge for 3-4 days.