Preheat your oven to 160C Fan / 180C / Gas Mark 6  and prepare two 20cm round sandwich tins with non stick baking paper.

Cream together your softened butter and light brown sugar using a spatula or an electric hand whisk. Do so until lighter in colour and fluffier in texture.

Gradually add your eggs one at a time. Mix briefly between each. Then add in your vanilla extract and mix once more briefly.

Add your gluten free flour, baking powder and xanthan gum and then mix with your spatula or electric hand whisk until combined.

Spoon the mixture evenly between the two tins and bake in the oven for 25-30 minutes until well risen.

Once baked, remove from the oven and allow to cool for 5 minutes in their tins before transferring to a cooling rack to fully cool.

Melt your dark chocolate (I do this in the microwave in 20 seconds bursts), put to one side to cool whilst making the rest of the frosting.

Place your softened butter in a large bowl and beat either with a spatula or with an electric hand mixer for a few minutes. The butter should change from a more yellow colour to being a lot paler.

Add your icing sugar gradually to the butter (we'd recommend doing this in two stages). I mix each addition of icing sugar for a few minutes before adding the second half.

Sieve in your cocoa powder and then mix again until fully combined.

Add in your cooled melted chocolate and mix until dispersed evenly, the colour is a lovely rich chocolate colour and it's a nice thickness to spread. If it feels a little too thick you can add a tsp of milk and mix it in to thin it out.

Place your chocolate and cream into a microwaveable bowl and heat for about 20 seconds, then mix. Return to the microwave and continue to heat for 10-second intervals, mixing in between, until the mixture is smooth and completely melted.

Carefully place one of your sponges onto your serving plate. Spread a layer of chocolate frosting on top of this and then drizzle some caramel on top of that.

Place your second sponge on top and cover the top with the rest of the chocolate frosting, drizzle with chocolate ganache and even more caramel on top (allowing the chocolate and caramel to drip down the sides) and finish with some mini millionaires shortbreads to decorate.

Slice and enjoy!