Cream together the butter and brown sugar with an electric whisk until pale and fluffy.
Add the molasses and vanilla and whisk again until fully blended.
Add one egg at a time and whisk each until fully combined.
In a separate bowl (or airtight container), weigh and mix together the flour, xanthan gum, bicarbonate of soda, ginger, cinnamon and salt, making sure any lumps are completely broken down.
Add the dry ingredients to the wet ingredients and stir until evenly combined.
Transfer the biscuit dough to a large piece of baking paper and use the paper to wrap the dough well (use a large piece of cling film as a second layer to hold together and seal if needed).
Refrigerate the dough for an hour or so, to firm up.
Line three or four baking sheets with baking paper (if you don't have this number, then just bake the biscuit pieces in two batches). Pre-heat the oven to 180 C/350 F/Gas 4.
Cut off about a third of the cold biscuit dough and on a well-floured surface (with a sprinkling of flour on top of the dough also), roll to a thickness of about ½ cm / ¼ inch.
Use your cookie cutters to cut template pieces according to the instructions provided by the manufacturer, and place carefully on the lined baking trays (try to keep larger pieces together and smaller pieces on a separate tray, so that you can remove the smaller pieces from the oven earlier if necessary).
Chill the cut biscuit dough pieces for about 30 minutes in the fridge (or 10 minutes in the freezer), before placing in the oven.
Bake for about 15 minutes, swapping the trays around part-way through to ensure an even bake.
Turn the oven down to 170 C/325 F/Gas 3 and continue to bake for a further 10 to 15 minutes, keeping a very close eye to ensure the biscuit does not burn. Be patient. The larger pieces take quite a while to bake and dry out enough to get a crisp bite and benefit from a slow drying process in the oven. If concerned the oven is too hot, then turn down a further and leave slightly longer.
Repeat this process until all the biscuit pieces are cut and baked. If possible, when the baking process is complete, turn off the oven and then place the trays back inside, allowing to cool with the oven (at this stage, you can place the pieces closer together to try and get them all in the oven at once).
Weigh and mix together the icing sugar and cream of tartar in a bowl.
Add the egg white and beat with an electric whisk until smooth, glossy and thick. The icing should be stiff enough to hold its shape very firmly. If it isn't, add a further spoon of icing sugar and beat again.
Using a piping bag with a small nozzle, pipe icing piece by piece, along each edge to be secured and gradually construct the house, holding each join together firmly and squarely to allow to stick and harden. If necessary use a selection of glasses or anything else you have to hand to 'prop' and hold together whilst the icing dries. Make sure that you cover any remaining icing with cling film (close to the icing surface) whilst you are waiting for the next stage, to ensure it remains usable.
Once the house is sturdy, use the remaining icing to decorate the house and any characters and to stick windows, doors, sweets, etc to the gingerbread.
Times are approximate and the gingerbread house may take less or more time to make, dependent on (particularly) the complexity of the decoration.The flour blend used (Gluten Free Alchemist Mix A) can be found on the Flours and Flour Blending page on the website.* Note: nutritional information is an estimate & may vary according to portion size/ingredient variants.