Heat the oven to 375°F (190°C) and line baking sheets with parchment paper. Make sure the butter is softened but not melted, since melted butter can cause the cookies to spread more than intended.

Whisk the flour, baking soda, and fine salt together in a medium bowl. This distributes the baking soda and salt evenly so the finished cookies bake consistently.

Beat the softened butter, granulated sugar, and packed light brown sugar until smooth and creamy. The mixture should look lighter and cohesive, with no large streaks of butter remaining.

Beat in the eggs one at a time, mixing after each addition, then blend in the vanilla extract. Scrape the sides of the bowl so the wet mixture is evenly combined.

Gradually mix the dry ingredients into the butter mixture just until no obvious flour remains. Avoid overmixing, which can make the cookies less tender.

Stir in the semi-sweet chocolate chips and the optional chopped walnuts or pecans. Fold gently so the chips and nuts are distributed without working the dough more than necessary.

Drop rounded tablespoons of dough onto the prepared baking sheets, leaving about 2 inches between portions. For thicker, more flavorful cookies, chill the portioned dough for 30 minutes to 24 hours before baking.

Bake for 9 to 12 minutes, usually 9 to 11 minutes, until the edges are golden brown and set while the centers still look slightly soft. Bake one sheet at a time when possible for the most predictable results.

Leave the cookies on the baking sheet for about 5 minutes after removing them from the oven. Transfer them to a wire rack to finish cooling, remembering that the hot baking sheet continues to cook the centers gently.