1. You will need a set of 3 star-shaped cookie cutters, plus a 2cm round cutter.
2. Preheat the oven to 170°C, gas mark 3. Line 2 large baking trays with baking parchment. Melt the butter, sugar and syrup together in a medium saucepan, stirring occasionally, then remove from the heat.
3. Sieve the flour, bicarbonate of soda and spices into a bowl then stir in the melted ingredients to make a stiff dough. Turn out onto a lightly floured surface and roll to a thickness of about 5mm.
4. Stamp out 6 of each size star and 12 of the 2cm rounds. Place on the baking sheets, leaving plenty of space between them. Chill for 10 minutes until firm.
5. Bake for 12–15 minutes until the biscuits are a light golden brown, then transfer to a wire rack and leave to cool. Meanwhile, mix together the icing sugar and egg white until smooth then spoon into a piping bag.
6. To assemble each tree, use the icing to stick one of the round biscuits onto the centre of one of the largest stars. Continue to build layers using 2 stars of each, descending in size, with a round disc and icing between each layer. Save one of the smallest stars for the top.
7. Decorate the reserved star with icing and leave to set, then fix it to the top of the tree with a cocktail stick. Brush the tips of the stars with a little water then dust with icing sugar.