Find a medium-sized mixing bowl, a knife and a small saucer to hold the castor sugar for coating.
Mix the sifted icing sugar, the castor sugar and ground almonds together in a mixing bowl. Add the lightly beaten egg and a few drops almond essence. Mix to a smooth firm dough in the bowl, then turn out on to a clean working surface. Sprinkle with a little castor sugar and knead lightly.</