Gather all your ingredients and measure them out.
In a large mixing bowl, whisk together the all-purpose flour, cake flour, salt, and cornstarch until well blended.
In another bowl, add the cold butter cubes, brown sugar, and white sugar. Beat with a mixer on medium speed until light and fluffy, about 2-3 minutes.
Add the eggs to the butter and sugar mixture and beat until fully incorporated and smooth.
Gradually add the dry ingredients to the wet mixture and mix on low speed until just combined. Do not over-mix.
Gently fold in the chocolate chips and chopped walnuts (if using) with a spatula until evenly distributed.
Cover the dough with plastic wrap and chill in the refrigerator for at least 30 minutes.
Preheat the oven to 350°F (175°C) while the dough chills.
Scoop the chilled dough onto prepared baking sheets, leaving space between each cookie.
Bake the cookies for 12-15 minutes until edges are lightly golden; centers may look slightly underbaked.
Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.