1 Put the eggs, sugar, flour, margarine and milk in a mixing bowl. Beat for 2 minutes with a wooden spoon to combine. Alternatively, use an electric mixer and beat for 1 minute.
2 Arrange 6 double cup cake cases in a ring on a dinner plate, leaving a gap in the centre. (This means using 2 cases for each cake: an alternative is to use a special microwave Muffin Pan which gives sufficient support, so that only one cake case needs to be used for each cake.)
3 Put I tablespoon of the mixture into each cake case and microwave on full power for 2 minutes.
4 Leave the cakes to rest for 1 minute, then turn onto a cooling rack and cool.
5 Continue with this method until all mixture has been used.
6 To make the icing: beat the water into the icing (confectioners') sugar. Beat in the colouring and butter, and use immediately to ice the cakes.
7 Decorate with coloured sugar strands.