Grease a 9x13 baking pan with cooking spray or butter.
Brown the Butter*
Put butter in a pan on the stove, and turn on medium heat.
Allow butter to melt and bubble, stirring occasionally to ensure butter is not burning.
Keep a close eye on the butter. It will go through a stage of bubbling, separating, then foaming. Once it gets to the foaming stage (about 10 minutes), watch until brown flecks begin coming through the top of the bubbles.
Stir briefly, allow to bubble for 15 more seconds, then remove browned butter from heat and pour into a glass or heat-proof bowl. You'll see flecks of brown in the butter, and it will be amber-colored.
Allow to cool for at least 15 minutes.
Make the Cookie Dough
In a large bowl, combine the brown sugar, eggs, and vanilla. Add in browned butter and stir until combined.
In a medium bowl, combine flour, baking soda, and salt. Add this to the brown sugar mixture and stir just until flour is completely mixed in.
Stir in chocolate chips until evenly distributed.
Bake the bars at 350 for 25-30 minutes. The bars should no longer be wiggly in the center when you jiggle the pan.
Cool for as long as you can stand it- then dig in!**
*Brown Butter: You do not have to brown the butter for this recipe, you can simply melt it. The recipe will not have quite the same richness, but will still be quite tasty and will save you a step if you need it!**Storage: These will keep covered on the counter for up to 3 days. They'll keep in the freezer for up to 3 months. If freezing, eat the bars within a day after defrosting.