Brown the butter and allow it to cool.
Whisk together the brown butter, brown sugar, and granulated sugar.
Add eggs and vanilla extract and mix until smooth.
In a separate bowl, whisk together flour, salt, baking powder, cornstarch, and baking soda.
Add dry ingredients to wet ingredients and mix until combined.
Fold in chopped chocolate.
Cover the dough and refrigerate for at least 1 hour. For even better flavor, chill overnight.
Preheat oven to 350°F and line baking sheets with parchment paper.
Scoop dough onto prepared baking sheets.
Bake for 10–13 minutes.
Cool on baking sheet before transferring to a wire rack.