Instructions

Step 1
Place butter, sugar and treacle in a saucepan over medium heat. Cook, stirring, until sugar has dissolved. Bring to the boil. Remove from heat. Stir in bicarbonate of soda. Transfer to a bowl. Cool for 20 minutes.
Step 2
Preheat oven to 180°C/160°C fan-forced. Line 2 baking trays with baking paper. Sift ginger, spice, baking powder and flour into a bowl. Add half the flour to butter mixture. Stir well. Add egg, stirring to combine. Stir in remaining flour until a sticky dough forms. Divide dough in half and shape into discs. Wrap in plastic wrap. Refrigerate for 1 hour.
Step 3
Roll 1 portion of dough between 2 sheets of baking paper until 4mm thick. Cut 20, 7.5cm x 8cm rectangles from dough, re-rolling scraps. Place on prepared trays, 2cm apart. Bake for 8 to 10 minutes or until golden and just firm to touch. Stand on trays for 5 minutes. Cool on a wire rack.
Step 4
Roll remaining dough between 2 sheets baking paper until 4mm thick. Cut 20, 7cm (sides) x 8cm (base) triangles from dough, re-rolling scraps. Place on prepared trays, 2cm apart. Using a 1cm x 2cm rectangular-shaped cutter, cut a door from half of the triangles. Reserve cut-outs and any dough scraps. Bake triangles for 8 to 10 minutes or until golden and just firm to touch. Stand on trays for 5 minutes. Cool on a wire rack.
Step 5
Place cut-out doors on trays. Roll scraps between 2 sheets of baking paper until 4mm thick. Using assorted Christmas shape cutters, cut 10 shapes, such as trees, wreaths and snowmen. Using a 1.5cm star-shaped cutter, cut 10 stars. Place on tray, 2cm apart. Bake for 4 to 5 minutes or until golden and just firm to touch. Stand on trays for 2 minutes. Cool on a wire rack.
Step 6
Make royal icing: Lightly whisk egg white in a bowl. Gradually add icing sugar, whisking until smooth and combined. Stir in lemon juice (cover icing with a damp sheet of paper towel to prevent it from drying out).
Step 7
To assemble: Spread about 2 tablespoons royal icing onto 1 cake board to cover. Place 2 triangles (1 with cut-out) on board, about 7cm apart, pushing into icing to secure. Spoon half the remaining royal icing into a large piping bag fitted with a 3mm plain how to gingerbread houses nozzle. Pipe icing onto edges of triangles. Attach rectangles to form a roof. Pipe royal icing along edges of house and across top of roof to resemble icicles and snow. Attach doors to house with icing. Repeat with more icing and house pieces.