Cream the butter and sugar together in a large bowl, beat in the egg, and lemon zest. Add the flour and baking powder and mix together until you have a firm dough. Roll into a ball then wrap and chill for 20 mins.
Preheat the oven to Gas 4, 180°C, fan 160°C. Grease 2 large baking sheets have ready Easter cookie cutters — chicks, eggs and bunny shapes.
Cut the dough in half then working with one half at a time, roll out the dough on a lightly floured surface until about 5mm thick. Press out shapes then transfer them to the baking sheet a little apart. Re-roll and cut out more shapes until all the dough is used up.
Use a skewer to make a hole in the top of each shape — this is where the ribbon will be threaded. Bake for 10mins until pale golden. Cool on a wire rack.
To decorate, mix 2tbsp of the lemon juice with the icing sugar until smooth. Divide the icing ito batches and colour as desired. Spoon a little icing over each biscuit then leave until completely set. Thread a coloured ribbon through each ribbon and hang them on a branch of willow, blossom or catkins.