In a large skillet, melt butter over medium-low heat stirring often until completely melted. Keep stirring the butter until it is foaming and bubbling.
Continue to stir until the foaming and bubbling starts to subside and the butter has turned a deep golden brown. Then remove from heat. This takes anywhere from 5-9 minutes and you'll be able to smell it once it starts to brown. Watch closely because the butter can go from brown to burnt in a matter of seconds.
Add the brown butter to the bowl of the stand mixer fitted with the paddle attachment and let it cool 5-10 minutes.
While the butter is cooling, preheat oven to 375°F and line cookie sheets with parchment paper.
Add the brown sugar and granulated sugar to the brown butter and beat until fully blended together. About 2-3 minutes.
Next, add the eggs one at a time, beating well after each egg. Then beat until the mixture turns pale in color. Another minute or so.
Mix in the vanilla extract.
Add the dry ingredients: baking soda, salt and all purpose flour. Mix on low just until combined.
Fold in the chocolate chips.
Using a medium scoop or 2 tablespoons, place cookie dough 2 inches apart on prepared cookie sheets.
Bake cookies on center rack in preheated oven for 8-10 minutes or until the edges are just starting to turn golden brown.
Let cookies cool 3 minutes on the pan and then remove to wire rack to cool completely.
Optional: finish with some flakey sea salt before serving.