1) In a bowl, cream together the sugar and butter, then mix in the egg and vanilla and almond extracts. 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 to 3 hours, or overnight.
2) Preheat the oven to 180C/Gas 8.
Divide the chilled dough in half and roll it out on a lightly floured pastry cloth to a 1-cm thickness. Lightly grease some baking trays. Cut the dough with a floured cutter; sprinkle with sugar. Transfer the biscuits to the prepared sheets and bake for 9 minutes.
3) For the icing, in a medium bowl, combine egg whites, sugar, and cream of tartar. Beat at low speed with an electric mixer until blended. Increase mixer speed to high, and beat 8 to 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.
*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, eggs with intact shells, and avoid contact between the yolks or whites and the shell.