Preheat the oven to gas mark 4/350oF/180oC/160oC fan and line a baking tray with parchment paper. No need to line if you have a non-stick baking sheet.
To a large bowl, add the flour, freeze-dried strawberry powder, cornflour, bicarbonate soda and salt. Mix them together and set aside.
In a stand mixer bowl with a paddle attachment, beat the butter and sugar until light and fluffy. Mix in the egg and vanilla extract then mix in the pink food gel. Pour in the dry ingredients and combine well until a dough is formed. Add in the white chocolate chips and mix until fully incorporated.
Roll the dough into 18 balls. If using scales each ball should weigh around 50g each. Place as many cookie dough balls on the baking sheet as you can fit ensuring there is space between each cookie to allow them to spread. You may need to bake in batches.
Bake the cookies in the middle of the oven for 11 minutes. Once baked, you can add some extra white chocolate chips to the tops of the cookies before they set for a better appearance. Allow the cookies to set on the baking sheet for 15 minutes then transfer the cookies to a cooling rack to completely cool.