In a bowl, combine cake flour, all-purpose flour, cornstarch, baking powder, and salt.
In a large mixing bowl, whisk sugar and melted butter on medium speed. Add egg one at a time.
Stir in flour mixture. Mix until just combined to avoid overmixing.
Stir in walnuts and chocolate chips. Leave the dough in the fridge for 45 minutes-1 hour.
Separate dough into balls using an ice cream scoop on a light-colored cookie sheet, then leave the dough in the fridge. Meanwhile, preheat the oven to 375F.
Bake cookies for 8-10 minutes or until golden brown on the top. Let them rest for at least 10 minutes to set.