Set a rack in the center of the oven and preheat oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone baking mats. Measure and have all ingredients at room temperature (butter and eggs).

Cream butter and sugars

In a large mixing bowl or the bowl of a stand mixer fitted with the paddle attachment, place the softened butter, granulated sugar, and light brown sugar. Beat on medium speed until light, fluffy, and pale in color, about 2–3 minutes, scraping the bowl down once or twice.

Add eggs and vanilla

Add eggs, one at a time, beating briefly after each addition until incorporated. Add the vanilla extract and mix until combined, scraping the bowl as needed.

Combine dry ingredients

In a medium bowl, whisk together the all-purpose flour, baking soda, and sea salt until evenly blended.

Mix wet and dry

With the mixer on low speed, add the dry ingredients to the butter-sugar-egg mixture in two additions, mixing just until combined and no streaks of flour remain. Do not overmix—stop as soon as the dough comes together.

Fold in chips (and nuts)

Using a spatula, fold in the semisweet chocolate chips and, if using, the chopped walnuts or pecans until evenly distributed throughout the dough.

Portion dough

Use a 1.5-tablespoon cookie scoop (or tablespoon) to portion rounded mounds of dough about 1 to 1 1/4 inches high, spacing them about 2 inches apart on the prepared baking sheets to allow for spreading. You can gently press a few extra chocolate chips onto the tops for an attractive finish.

Bake

Bake one sheet at a time in the preheated 350°F (175°C) oven for 9–12 minutes, rotating the sheet halfway through baking for even browning. Cookies are done when edges are set and lightly golden while centers still look slightly soft — they will continue to set as they cool.

Cool

Allow cookies to cool on the baking sheet for 5 minutes to firm up, then transfer to a wire rack to cool completely. Repeat with remaining dough.

Storage

Store cooled cookies in an airtight container at room temperature for up to 4 days. To keep cookies soft, place a slice of bread in the container; replace as it dries. Dough can be refrigerated up to 3 days or frozen for up to 3 months (portion dough and thaw/bake as needed).