• Preheat oven to 180°C and grease and line a a 20cm square springform baking tray.
• In a large bowl mix gluten free self raising flour, xanthan gum, salt and cocoa powder.
• In a separate bowl whisk the eggs with the light brown and granulated sugar until combined. Add melted dark chocolate, dairy free milk, vegetable oil, vanilla extract and coffee and whisk until everything is combined.
• Fold the dry ingredients into the wet until you have a smooth chocolatey batter. Pour the batter into your lined tin and bake in the middle of the oven for around 45 minutes, or until an inserted knife comes out clean (this may take slightly more or less depending on your oven, start check at around 40 minutes).
• Remove from the oven and leave to cool in the tin for half an hour before transferring to a wire rack to cool completely before you make the buttercream.

Make the topping

• Make the buttercream by adding the dairy free butter block to a large bowl and beat until creamy. Gradually add the icing sugar and cocoa powder, continuing to beat until fully combined and creamy. The buttercream will take a little while to come together so keep mixing! Add the dairy free milk and beat again.
• Spread (or pipe if you want it to be neater) the buttercream onto your cake and top with decorations of your choice. Store in an airtight container for up to 4 days.