Cut out the templates for each house – 1 roof piece, 1 side piece and 1 front/back piece. Line 2 baking sheets with baking paper. Roll out the dough approximately the thickness of a £1 coin on a floured surface and cut out the pieces with a sharp knife – you will need to cut 2 pieces with each template.
Decorate the house fronts with the royal icing, pipe the windows and door and any architectural details. Leave the icing to harden for an hour or 2.
To construct the house, attach the 2 sides to the house front with royal icing, then attach the back panel.
When the icing has set you can attach the roof pieces. You may need to file them down with the grater to ensure a snug fit. Use folded up kitchen roll to support the first roof piece before attaching the next.
Decorate the roof by piping on tiles and a covering of snow!