Preheat the oven to 180’C/ Fan 160C / Gas Mark 4. Line a 2lb baking tin with a baking liner and set to one side.

Melt the chocolate over a bowl of hot water until smooth, then remove from the heat. Leave to stand and cool slightly while you begin the cake batter.

Add the oil, sugar and buttermilk to the bowl and beat together for 30 seconds using an electric whisk. Add the eggs and beat for another 30 seconds.

Sift in the gluten free flour and cocoa powder then beat the mixture again until there are no lumps of flour. 

Pour in the melted chocolate and fold in with a spatula or wooden spoon. Once mixed, pour into the lined loaf tin and bake for 50-60 minutes, until a skewer inserted in the middle comes out clean. Remove and cool completely.

Beat the butter, icing sugar, milk and vanilla extract together in a mixing bowl until pale and smooth. 

Spoon the frosting into three separate bowls and then add food colouring to each - I used pink, purple and yellow. Mix well until there are no streaks of colour.

Lay a sheet of clingfilm out on your work surface. Spoon the first colour onto the clingfilm into a rough sausage shape, not longer than the piping bag.

Spoon the second colour into a sausage next to it, and the third next to that, so the three colours are lined up together. (You can do this by piping the colours onto the clingfilm but I find this wastes too many piping bags and it doesn't have to be perfect!)

Roll the colours up together using the clingfilm, so that you have one, long, fat sausage shape - then simply drop this into your piping bag with the short, open end nearest the nozzle.

Squeeze the colours down to the nozzle.

If your cake has risen a lot, you can trim the top with a large, serrated knife, to flatten it. Once ready and the cake has cooled, take it out of the tin.

Pipe the buttercream onto your cake however you like - I used a 1M Piping Nozzle to pipe these little rosettes all over mine.

Decorate with a variation of whole and crushed Mini Eggs and then slice up and serve!