1) In a bowl, cream together the sugar and butter, then mix in the egg and vanilla and almond essences. In another bowl, stir together the flour, bicarbonate of soda and cream of tartar; mix the dry ingredients into the creamed mixture, then cover and refrigerate for 2-3 hours, or overnight.
2) Preheat the oven to 180C/Gas 4.
3) Divide the chilled dough in half and roll it out on a lightly floured pastry cloth to a 0.5cm thickness. Lightly grease some baking trays. Cut the dough with a floured biscuit cutter; sprinkle with sugar. Transfer the biscuits to the prepared sheets and bake for 9 minutes.
4) In a medium bowl, combine egg whites, sugar and cream of tarter. Beat at low speed with an electric mixer until blended. Increase mixer speed to high, and beat for 8-10 minutes, or until mixture holds a peak. Cover with a damp cloth when not in use. Separate into bowls and add food colouring, if desired.
5) Remove biscuits from oven and, when cool, ice with royal icing.
*RAW EGG WARNING
Food Network Kitchens suggest caution in consuming raw and lightly cooked eggs due to the slight risk of salmonella or other food-borne illness. To reduce this risk, we recommend you use only fresh, properly refrigerated, clean grade A or AA eggs with intact shells, and avoid contact between the yolks or whites and the shell.