Mix flours, salt, baking powder, and baking soda in a bowl.

Start by adding the cold butter to the bowl of a stand mixer, giving it a quick pulse with the paddle attachment to loosen the butter.

Add the sugars and stir until just combined.

Add the chocolate chips and walnuts and stir until just combined.

Add the dry ingredients and stir until a breadcrumb-like consistency.

Add the beaten eggs and stir until just combined.

Form into rough balls weighing 125g each, and freeze for at least 90 minutes, but it's better to freeze overnight.

Preheat the oven to 185c/365f with parchment-lined baking sheet inside

Once the oven has come up to temperature, put the frozen dough balls at least 2 inches apart on the preheated baking sheet.

Bake for 17 min.

Let cool 10 minutes before moving to a wire cooling rack.