Line baking sheets with parchment paper. Set aside.
In a stainless steel skillet (or another light-bottomed pan) over medium-high heat, melt butter, swirling the pan occasionally. The butter will begin to foam, which signals the water in the butter is boiling off. (Watch closely at this stage.) Tiny brown specks of milk solids will begin to appear at the bottom of the pan; constantly stir and scrape these off using a spatula so they don't stick.
As soon as the butter turns chestnut brown and smells nutty, remove the pan from the heat. Pour the browned butter into a large heat-safe bowl.
To the hot browned butter, add the brown sugar, stirring to combine. Set aside to cool for 15-20 minutes.
To a medium bowl, add the flour, baking soda, salt, and baking powder. Whisk to combine.
Once the butter mixture has cooled, add eggs and bourbon. Whisk to combine.
Using a rubber spatula, gradually mix in the flour mixture, stirring to combine.
Fold in most of the chocolate chips, reserving a few for the tops of the cookies (optional).
Using a 3-tablespoon scoop, drop balls of dough onto the lined baking sheets, leaving about an inch between each cookie. Top with reserved chocolate chips (if using). Cover the dough balls and transfer to the refrigerator to chill for 24 hours.
Remove the chilled cookie dough from the refrigerator. Let it rest at room temperature for 30 minutes before baking the cookies.
Preheat oven to 350°F.
Bake cookies for 12-14 minutes, or until golden brown. (I prefer these slightly underdone, so I will start checking at 10 minutes.)
Remove from oven. Sprinkle salt on the tops of the warm cookies.
Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.