Method

Bring butter to room temperature so it's soft but still holds shape (about 30–60 minutes). Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone baking mats.

In a large mixing bowl or stand mixer fitted with the paddle attachment, beat the softened unsalted butter, granulated sugar, and light brown sugar together on medium speed until light and fluffy, about 2–3 minutes. Scrape down the bowl once.

Add the eggs one at a time, beating briefly after each until incorporated. Mix in the vanilla extract until blended. The mixture may look slightly curdled — that's fine.

In a separate bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt until evenly combined and free of lumps.

With the mixer on low speed, add the dry ingredients to the butter-sugar-egg mixture in two additions. Mix just until no streaks of flour remain; avoid overmixing to keep cookies tender.

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

Scoop dough by heaping tablespoonfuls or using a 1.5-tablespoon cookie scoop (about 28–32 g each) onto the prepared baking sheets, spacing them about 2 inches apart to allow spreading. For uniform cookies, gently roll each scoop into a ball and slightly flatten the top with your fingers.

If using, sprinkle a tiny pinch (a few grains) of coarse sea salt onto the top centre of each cookie dough ball to enhance flavor.

Bake one sheet at a time in the preheated oven for 10–12 minutes, until the edges look set and the centers still appear slightly soft. Rotate the pan halfway through baking for even color. Avoid baking until fully firm—cookies will continue to set as they cool.

Allow the cookies to cool on the baking sheet for 5 minutes to finish setting, then transfer them to a wire rack to cool completely. Store in an airtight container at room temperature for up to 4 days.

Chocolate Walnut Cookie Recipe