Preheat your oven to 375°F (180°C).

In a large bowl, whisk together the flour, baking soda, and salt. These are your dry ingredients.

In a separate medium sized bowl, use a hand mixer on low speed to cream the butter, white sugar, and brown sugar together until mixed well. It should look light and fluffy.

Add the egg and pure vanilla extract to the butter sugar mixture and mix until well combined. These are your wet ingredients.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the chopped walnuts and chocolate chunks with a spatula.

Cover the bowl with plastic wrap and chill the dough for about 30 minutes in the refrigerator.

Using a cookie scoop or spoon, drop the cookie dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10 -15 minutes (depending on your oven), or until the edges are golden brown and the centers are set.

When your cookies are done, take them out of the oven, and let them cool on the cookie sheet for a few minutes. Then use a spatula to shift them onto your wire rack to cool.