Preheat oven to 350°F (180°C). Prep two trays with baking paper.
Sift flour and ginger into a mixing bowl.
Pop butter, treacle and brown sugar into a pot. Stir over a low heat until melted and combined. Turn off the heat and stir in baking soda.
Add your liquid ingredients into your mixing bowl (with dry ingredients) and mix lightly, then add the beaten egg and mix well until it comes together into a soft dough.
Transfer your dough to a lightly floured board / bench and knead for a minute until smooth.
Roll your dough out (on your floured surface) to a thickness of about 1/8" (or 3mm). Using a gingerbread person cutter (or any shape you wish) cut out shapes and transfer to your baking tray. Re-roll leftover dough until all the dough has been used.
Bake one tray at a time, for 12-15 minutes or until golden.
If desired, ice with royal icing.