Preheat the oven to 350°F. Butter and line a 9x16 nonstick pan.
Start by melting the butter on the stove, but then continue to let the butter simmer. It'll start with foam on top. Then, the foam will disappear as the milk solids begin to cook and sink to the bottom. Eventually, the solids will turn a pretty golden brown color. At this point turn off the heat, and continue stirring until the solids are just past amber-colored and just on the verge of burnt. Pour immediately into a heat-proof bowl and chill for 30 minutes to cool slightly.
In your stand mixer, add the brown sugar and butter. Whip these together for 5 minutes until it goes from oily to creamy in texture. Add in the eggs while the mixer runs on medium-high speed. Then, add the vanilla and whiskey. At this point, it should be velvety smooth.
Mix in the flour, baking soda, and sea salt.
Fold in the chips and then press the dough into the prepared pan. Top with extra chips as needed.
Bake for 25 to 30 minutes (up to 45 minutes if you use a glass pan instead), depending on your oven's accuracy. A toothpick should come out crumby but not coated in raw batter.
Allow them to cool completely so the center sets. Then, cut into at least 16 pieces.