Recipe: Happy Birthday Cup Cakes

I think this is a great idea for any party. Also, if you aren't too keen of making the icing yourselves, there is always commercially made coloered icing available in the supermarkets! I think it's particularly good for those who can't have too much sweet things! See what you think! ^_^
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Happy Birthday Cup Cakes
from Lorna Wing's "Party!food", p.85

"I think these bite0sized orange cup cakes are a fun way to celebrate a birthday, anniversary, or festive occasion. Pipe a message on them and decorate however your artistic talents allows." MAKES 48.

For the orange cup cakes
3 oz. /95g [7 T.] unsalted butter, softened + extra for greasing
4 oz/110g caster sugar [heaped cup granulated sugar]
Finely grated zest of 1 medium oranges
1 medium egg
2 T. orange juice
5 oz./ 165 g self-raising flour [heaped 1 cup self-raising flour], sifted

For the glace icing
9 oz./250g icing sugar [2 cups confectioners' sugar], sifted
4 T. warm water
1 T. orange flower water, or orange juice, strained

For the royal icing
3 large egg white, lightly whisked
15 oz. 425g icing sugar [3 cups confectioners' sugar], sifted
2 different food colorings
** you will also need 4 sets of 12 mini muffin tins 1 in/ 4cm in diameter, 48 small paper cup cake cases, 2 piping bags, 2 small star nozzles and 1 small plain nozzle.

Heat the oven to 350F/180C/ Gas 4 and line the muffin tins with the paper cases. Beat the butter, sugar and orange zest together for 2 minutes or until light and creamy. Beat in the egg and orange juice, then fold in the flour.
Divide this mixture between the muffin tins and bake until risen and golden. Lift the cakes out onto a wire rack to cool.
Make the glace icing by putting the sugar in a bowl and making a well in the center. Slowly incorporate the water until the icing is very smooth. Mix in the orange flower water or strained orange juice.
Use the glace icing immediately or a skin will form on it. Spoon the icing onto the cakes and allow it to set for about 1 hour.
Mix the egg whites and sugar together for the royal icing until stiff but pipeable. Divide into third and tint one batch with another color and leave the remainder white.
Decorate the edges of the cake with the white royal icing using a star nozzle. Pipe the message on the cake with one color, using the other star nozzle. Use the other colored icing and the plain nozzle to decorate the rest with hearts and flowers. Let dry for 2 hours before serving.

Advance preparation: decorate the cakes 2 days ahead and store in single layers in airtight containers.
Freezing: Freeze the undecorated cakes 1 week before.