Preheat the oven to 360 F (180 C). Prepare a 12-cup mini loose bottom dessert tin with butter (My dessert tin features 2 x 3 inch cups). In a large mixing bowl, cream the butter and sugars with an electric mixer until pale and creamy. Add the vanilla extract. Then add one egg at a time and continue to beat until mixture is combined and creamy. Boil the kettle and pour out 1/2 cup water and set aside.

In a separate bowl, sift the plain flour, cocoa powder, baking powder and baking soda and lightly whisk. Add the dry ingredients to the wet, along with the hot water and gently fold with a spatula. Add the sour cream and fold until the mixture is combined.

Carefully spoon the cake mixture into your prepared cake tin – it makes 10 mini cakes. Pop into the oven for 20 minutes or until the cake springs back lightly to the touch. Leave the cakes to cool for about 5 minutes before carefully transferring the cakes to a wire rack to cool completely.

To make the chocolate frosting, place your softened butter in a large mixing bowl and beat with an electric mixer on medium speed until smooth and creamy. Sift in your powdered or icing sugar, add your milk and beat until combined. Meanwhile melt the chocolate in a microwave, stirring in between 20 second bursts, until just melted.

Next you will want to add in your melted chocolate to the buttercream mixture, ensuring the chocolate is smooth and melted but is not warm at all. Beat until the chocolate is completely mixed through. Use a small spatula to spread the frosting onto the cakes, then sprinkle over a few chocolate shavings.