In a bowl, mix together the flour, gingerbread spices, salt and baking soda.
In another bowl, beat butter with brown sugar until creamy.
Then add the egg, vanilla and molasses and mix again to incorporate.
Add the dry ingredients, flour, spices, baking soda and salt and mix until you have a smooth ball of dough. Cover and let rest in the refrigerator for 30 minutes.
Cut out shapes on the dough previously rolled out on a lightly floured surface. Place the cut out cookies on a baking sheet covered with baking paper and bake for 10 minutes at 347°F / 175°C.
Place sifted powdered sugar and water in a large bowl and beat with an electric whisk for 5 minutes until desired consistency is reached.
Place the icing in a piping bag and decorate your snowflake cookies. Let them dry for one hour before eating.