Brown the Butter: Melt 1 cup of unsalted butter over medium heat in a light-colored saucepan for 5-7 minutes until golden brown and nutty. Transfer to a heatproof bowl and cool for 10 minutes.

Prepare Dry Ingredients: Whisk together 1.75 cups of flour, 1 tsp of baking soda, 0.5 tsp of baking powder, 1 tsp of cornstarch, and 0.5 tsp of salt in a bowl.

Cream the Butters and Sugars: Beat the cooled brown butter with 1 cup of dark brown sugar and 0.5 cup of granulated sugar for 3 minutes until light and fluffy. Add 2 eggs one at a time, mixing well, then add 2 tsp of vanilla extract.

Combine the Ingredients: Gradually mix the dry ingredients into the wet until just combined. Gently fold in 2 cups of chocolate chips.

Chill the Dough: Cover the bowl with plastic wrap and refrigerate for at least 30 minutes, up to 48 hours.

Bake the Cookies: Preheat oven to 350°F (175°C). Line baking sheets with parchment paper. Scoop 2-tbsp portions of dough, spacing them 2 inches apart. Optionally, press in extra chocolate chips and sprinkle with sea salt. Bake for 10-12 minutes.

Cool and Serve: Let the cookies cool on the baking sheet for 5 minutes before transferring to wire racks.