Preparation Steps

• 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. 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 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 vanilla. Whisk to combine.
• Using a rubber spatula, gradually mix in the flour mixture.
• Fold in the chopped chocolate.
• Using a 3-tablespoon scoop, drop balls of dough onto a baking sheet lined with parchment paper. Cover the dough balls and transfer to the refrigerator to chill for at least 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 (175°C). Line baking sheets with parchment paper.
• Place the dough balls onto lined baking sheets, leaving about an inch between each cookie. Bake for 12-14 minutes, or until golden brown around the edges and slightly underdone in the center.
• Remove from oven. Sprinkle flaky sea 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.