Step 1

Line 2 baking trays with baking paper. Use an electric mixer to beat the butter and sugar in a large bowl until light and fluffy. Add the plain flour, rice flour and mixed spice, in 3 batches, beating well after each addition.

Step 2

Turn the dough onto a lightly floured surface and knead until smooth. Roll out the dough between 2 sheets of baking paper until 5mm thick. Cover with plastic wrap. Place in the fridge for 30 mins or until firm.

Step 3

Preheat oven to 150°C. Use a 7.5cm tree-shaped cutter to cut shapes from the dough, rerolling excess. (To freeze, see tip in notes.)

Step 4

Place on lined trays, 3cm apart. Bake for 15 mins or until light golden. Transfer to a wire rack to cool.

Step 5

To make the royal icing, whisk the egg white and lemon juice in a medium bowl. Gradually add the icing sugar, stirring well after each addition, until a smooth paste forms. Divide into 5 portions. Use food colouring to tint 4 portions different shades of green, leaving 1 portion white.

Step 6

Divide the white icing portion in half. Reserve 1 portion to make the baubles. Place half the remaining white icing portion in a piping bag fitted with a 1.5mm plain nozzle. Pipe around the edges of the tree bases to make a border. Set aside to set. Add a little extra egg white and lemon juice to remaining white icing portion to make a runny paste. Spoon a little runny icing into the centre of the bases and use the back of the spoon to spread to the border. Set aside to set.

Step 7

Place half of 1 green icing portion in a piping bag fitted with a 1.5mm plain nozzle. Pipe around edges of one-quarter of the trees to make a border. Set aside to set. Add a little extra egg white and lemon juice to remaining green icing portion to make a runny paste. Spoon a little runny icing into the centre of the trees and use the back of the spoon to spread to the border. Set aside to set.

Step 8

Repeat, in 3 more batches, with the remaining green icing portions and the remaining trees.

Step 9

Pipe remaining white icing in piping bag over the green trees in a zig-zag pattern to make the garlands. Divide reserved white icing into 3 portions. Use food colouring to tint each portion blue, pink or yellow. Place yellow icing in a piping bag fitted with a 1.2mm nozzle. Pipe over the biscuits to make baubles. Repeat, in 2 more batches, with pink and blue icing. Set aside to set.