Mix all the dry ingredients together in a bowl

Add the vanilla and butter and rub in with your fingertips until it forms crumbs (you could add green food colouring at this point if you wish but don't make it too dark!)

Start to knead and form the dough, adding milk if required but don't make the dough wet

Cut circles with a round cutter that's big enough to fit the shamrock cutter inside. I used a 3 inch circle with a 1.5 inch shamrock

Put the cookies on the baking sheet and one by one place the shamrock cutter in the centre of each to use as a shape guide. Pour some green coloured sugar inside then slowly lift it away

Let cool on the baking sheet then when cooled knock off the excess sugar

Mix the leftover dough with sprinkles and make shamrock shaped cookies