1-First Step: Mise en place and oven prep Preheat your oven to 400°F and line a baking sheet with parchment paper. Measure all ingredients ahead of time so the process moves quickly. Chop walnuts if not already chopped and set aside. Using a 3 tablespoon scoop will give uniform cookies, so have that ready.

2-Second Step: Creaming the fats and sugars Place 1 cup cold salted butter cubed into the mixer bowl. Add 1/2 cup dark brown sugar, 1/2 cup light brown sugar, and 1/2 cup granulated sugar. Mix on low for 30 seconds to combine the cubes into the sugars and prevent a cloud of sugar, then increase to medium speed and beat for 4 minutes until the mixture is light and fluffy. Cold butter helps reduce spread and gives a slightly denser, chewier cookie.

3-Third Step: Adding eggs and dry activators Add 2 eggs and 2 teaspoons vanilla to the creamed butter and sugars. Sprinkle in 1 teaspoon kosher salt, 1 teaspoon baking soda, and 2 teaspoons cornstarch. Mix on medium for about 1 minute until smooth, pausing to scrape down the bowl so everything incorporates evenly. The cornstarch is a small but powerful addition; it relaxes protein development and creates a tender interior.

4-Fourth Step: Incorporating flour With the mixer on low speed, gradually add 3 cups all purpose flour. Mix only until combined to avoid overworking the gluten which can make cookies tough. The dough should be thick but still scoopable; if it feels excessively wet, add a tablespoon of flour at a time until you reach a soft, slightly sticky consistency. If you need thicker cookies, a slight increase in flour helps but be careful not to add too much or cookies will become cakey.

5-Fifth Step: Mixing in chocolate chips and walnuts Still on low speed, fold in 2 1/2 cups chocolate chips and 1 1/2 cups chopped walnuts until evenly distributed. If you prefer chunks of chocolate, reserve 1/2 cup of chips to press on top of the dough rounds before baking. For even nuttier flavor, toast walnuts for 5 to 7 minutes at 350°F prior to chopping and mixing. Toasting concentrates aroma and brings out natural oils.

6-Sixth Step: Portioning the dough Using a 3 tablespoon scoop, portion dough onto the prepared baking sheet about 2 inches apart to allow for slight spreading. If you want very rounded, bakery-style tops, pack the scoops slightly and press a few extra chips on top of each dough mound. For taller cookies, chill scooped dough 30 to 60 minutes before baking.

7-Seventh Step: Baking Bake at 400°F for 8 to 9 minutes, or until the edges and tops are lightly golden while centers still look soft. Baking at a higher temperature helps brown the outside quickly and keeps the middle tender. If baking from frozen, bake at 375°F and add 1 to 2 minutes to the time.

8-Final Step: Cooling and serving Remove cookies from the oven and cool on the baking sheet for 2 to 3 minutes so they set. Transfer to a wire rack to cool completely. These cookies are best enjoyed the same day while chips are melty and centers are soft, but they also store well. Serve with a cold glass of milk, coffee, or tea.