Pot of Gold at the End of the Rainbow

For the cake: Bake the cake in a lined 23 cm | 9" round cake tin. Remove when a cake tester comes out clean from the centre. Remove to a wire rack to cool.

Once the cake is cool, turn out from the tin and level the top with a serrated knife. Cut one-third of the cake away from the main part and reserve for use in other desserts. Use a smaller knife to cut out a semi-circle from the centre, leaving you with a rainbow shape.

For the buttercream: Divide the butter cream between seven bowls. Add a few drops of each food colouring to six bowls respectively. Beat the colour into the buttercream until uniform.

Spoon the red buttercream into a piping bag fitted with a petal tip. Chill the five coloured buttercreams. Cover the rainbow cake with a thin layer of white buttercream. Spread the remaining buttercream over the initial layer and smooth down.

Pipe two rows of folded petal shapes onto the edge (and down the sides) of the cake, working the tip carefully up and down for each petal. Spoon the other coloured buttercream into piping bags fitted with petal tips.

Repeat this step for the other buttercream colours, working carefully and methodically. Once you get to the purple buttercream, pipe the first row as you did with the other colours, and then fill in the inner side of the cake, working from the bottom upwards.