Preheat oven to 180C / 350F /160C fan forced. Line 2 large baking trays with baking paper.
Sift together the flour, baking soda and salt and mix to distribute evenly.
In a separate bowl, beat together the butter and sugar until lightened and fluffy.
Scrape down the sides of the bowl and add half the flour mix. Beat until just combined. Add the milk and remainder of the flour and mix until it just starts to come together.
Finally, add the candied ginger and give the mix another beat until mixed through and the dough is clumping.
Pull the dough together with your hands then take approximately 2 teaspoons full of dough, roll into a ball and then gently press to flatten the top just slightly. Roll the top in the demerara sugar and place (sugar side up) on baking trays 1-2 inches apart.
Bake for 12-13 minutes or until the edges are just starting to turn golden. (the longer you bake them the crispier they’ll get)