Preheat your oven to 160C Fan / 180C and prepare a 2lb loaf tin with baking paper.
Cream together your softened butter and sugar until light and fluffy (I use an electric hand mixer).
Add in your eggs, gluten free self raising flour, baking powder, xanthan gum, sifted cocoa powder, ground almonds and milk. Mix together until combined using your electric hand whisk.
Fold in your chocolate chips carefully.
Spoon the cake mixture into your tin. Ensure it's as even as possible. Place in the oven for about 50 minutes until cooked through.
Remove from the oven and allow to cool in the tin before moving to a cooling rack.
For the icing:
Melt your dark chocolate (I do this is the microwave in 20 seconds bursts), put to one side to cool whilst making the rest of the buttercream.
To make your icing, place your butter in a stand mixer (or electric hand whisk if you don't have a stand mixer), mix on its own on a high speed for about 5 minutes. The butter should change from a more yellow colour to being a lot more pale.
Add your icing sugar gradually to the butter (I do this in two stages). I mix each addition of icing sugar for around 3 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 too thick, add a drop of milk and mix.
Mix in 2 Crunchies broken into smaller pieces.
To decorate:
Spread your icing all over the top of the cake and then cover with more Crunchie bars just before slicing. Enjoy!