1.Beat butter, syrup and sugar in a medium bowl with an electric mixer until creamy and paler in colour. Add egg yolk; beat until just combined. Add combined sifted flour and spices; stir until mixture just comes together.
2.Knead dough gently on a lightly floured surface until smooth. Cover with plastic wrap and refrigerate for 30 minutes or until firm.
3.Preheat oven to 180°C. Grease oven trays and line with baking paper.
4.Roll dough on a lightly floured surface until 3mm thick. Using a 5cm square cutter or cardboard template, cut out 39 squares. Cut 13 of the squares in half to form two triangles.
5.Arrange squares on trays about 3cm apart. Place a triangle on top of each square slightly overlapping to form a house shape, then press gently over the join to seal. Make a small hole in the top of each house, not too close to the edge, using a skewer.
6.Bake cookies for 10 minutes or until light golden. Stand cookies on trays for 5 minutes before transferring to wire racks to cool.
7.Stir chocolate in a medium heatproof bowl over a medium saucepan of simmering water until smooth (don’t let water touch base of bowl).
8.Fill the piping bag with melted chocolate and cut a small hole from the tip of the bag. Pipe chocolate onto biscuits using picture as a guide. Stand for 15 minutes or until chocolate is set.