In a large bowl, mix together flour, baking soda and salt.
In medium saucepan, set over medium-low heat, melt the butter. Take out a silicon whisk and give the butter a stir. It will begin to foam up and bubble. Stirring frequently, allow it to keep going until it goes from a pale yellow color to a light brown color. Once it hits a light brown color, I like to give it a few more stirs just so I can monitor the color. This process happens quickly so don’t walk away! Keep stirring it until it goes from a light brown color to deep golden brown. Remove it from the heat and give it a few more stirs.
I like to let it continue to cook until it’s dark brown. Immediately pour it into a large bowl. Whisk in the two teaspoons of water. Allow the brown butter to cool for about 10 minutes. (If you don’t do this, when you add the chocolate, it’ll melt.)
Next, whisk in the sugars. And then, add the eggs and vanilla. Pour into the dry ingredients and mix until combined. Lastly, fold in chocolate chips and walnuts (if using). Stick in fridge for 1 hour to chill.
Preheat oven to 350F. Scoop out 2-ounce balls of dough and roll them between your palms; place them onto a parchment-lined baking sheet spacing them 4 inches apart.
Bake for 8 minutes. At the 8-minute mark, remove them from the oven to shape them (this is optional). Rotate the pan and bake for an additional 3 to 4 minutes, until the edges are lightly golden brown.