Add the dark brown sugar, honey and butter to a large saucepan and place on a low heat. Continue to heat, stirring occasionally, until the butter has melted and the mixture has combined to form a smooth liquid. Do not let it boil. As soon as it's melted, remove from the heat and leave to cool for 5 minutes.

Meanwhile, mix the plain gluten free flour (see notes below if using self-raising), baking powder, xanthan gum, mixed spice and ground almonds to a large mixing bowl and stir well.

When the sugar/honey mixture has cooled slightly (you want it warm, not hot, so it doesn't cook the egg!) pour it into the flour mix and stir well until it starts to form a sticky dough.

Lightly beat the egg in a small bowl then add to the mixture. Continue to stir until the mixture has combined into a thick, sticky dough, with no clumps of flour. Don't worry - it's supposed to be super sticky at this stage!

Now for the most important part - CHILL. Scrape the mixture out into some clingfilm (or just pop the mixing bowl into the fridge) and leave to chill for at least 2-3 hours. Ideally overnight to allow all the flavours to really be absorbed by the dough.

When the dough has completely chilled, preheat the oven to 180'C / Fan 160'C / Gas Mark 4. Remove the dough from the fridge.

Break off small pieces of dough and roll into balls, approximately an inch in size. Working as quickly as you can to keep the dough as chilled as possible, place the balls of dough on a baking tray with plenty of space between them.

Place the tray in the oven and cook for 10-12 minutes, until the cookie dough balls have transformed into small domes which are golden brown on top. Remove from the oven and leave to cool completely before removing them from the tray. (Note: If you have to cook them in batches, keep any uncooked dough in the fridge before placing in the oven if you can, to avoid it warming up too much).

Once the biscuits have cooled, make the glaze by adding the icing sugar to a bowl then adding the boiling water, 1 tbsp at a time, until you have a thick glaze. Dip the biscuits into the glaze until coated, then place on a cooling rack until completely set (you might want something underneath to catch any drips!).