Step 1

Preheat the oven to 350°F. Line baking sheets with parchment paper, or use silpat mats.

Step 2

In a large bowl, use an electric mixer to cream the butter and two sugars together until light and fluffy. Add the vanilla, then the eggs, one at at time, and mix well.

Step 3

Sift together the flour, baking soda, and salt and add to the bowl mixing on low speed, just until combined. Stir in the chocolate chunks (and walnuts, if using).

Step 4

Cover the bowl with plastic wrap and refrigerate until the dough is firm (1 to 2 hours or more).

Step 5

Scoop out the dough by the heaping tablespoonful onto the prepared baking sheets, using a 1¾-inch-diameter ice cream scoop or a rounded tablespoon. Dampen your hands and flatten the dough slightly. Bake for 10 to 13 minutes (the cookies will seem underdone in the middle and lightly browned on the edges). Remove from the oven and let cool slightly on the pan, then transfer to a wire rack to cool completely.