If you know someone who has a passion for the colour turquoise, little could be more appropriate for a birthday than a cake covered in that colour. Gather some simple ingredients and mix up the icing for a cake your friends, family and guests will find uniquely appealing.
Spoon one batch of white icing into a large mixing bowl.
Put six drops of sky blue food colouring into the icing. Add one drop of lemon yellow food colouring.
Mix the icing and food colourings together until they are entirely uniform in colour. The colour will be a light turquoise colour. If you like this colour, ice the cake. If the colour is too light, darken it with more colouring.
Continue adding more food colouring until it is dark enough. Add six drops of sky blue and one drop of lemon yellow every time, then stir to test the colour.
Don't vary the food colouring ratio or the colour won't come out as turquoise.