Preheat your oven to 410°F and line two baking sheets with parchment paper. In a medium bowl, whisk together 1 ¾ cups all-purpose flour, ¾ cup cake flour, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon cornstarch, and ¾ teaspoon salt. Set aside.

In a large bowl, beat 1 cup cold butter, ¾ cup packed brown sugar, and ⅓ cup granulated sugar until the mixture becomes smooth and creamy. Add 2 eggs and 2 teaspoons vanilla extract, mixing until just combined.

Slowly incorporate the dry ingredients into the wet ingredients, mixing until a dough forms. Gently fold in 1 ½ cups chocolate chunks and 1 cup walnuts until evenly distributed.

Scoop the dough into 6-ounce balls, approximately the size of a tennis ball, and place them on the prepared baking sheets with space between each. Bake for 9-12 minutes, or until the edges turn golden brown and the centers appear soft.

Allow the cookies to cool on the baking sheet for 10 minutes before transferring them to a wire rack to set completely.