Preheat the oven to 350°F
To make the brown butter, heat the two sticks of butter in a saucepan over medium-high heat until it turns a light amber color. This should take between 5-6 minutes
Once browned, take the butter off the heat and place it into the freezer to cool and harden. The goal is for the butter to become almost completely re-solid, similar to the consistency of softened butter
While the butter is cooling, whisk together the dry ingredients. In a large mixing bowl, combine the flour, baking powder, baking soda, and salt
In a separate mixing bowl or stand mixer, combine the brown sugar, white sugar, eggs, vanilla, and browned butter. Whisk until thoroughly combined
Add the dry ingredients to the mixture and mix until just combined
Mix in the chopped bittersweet chocolate, saving about 1/4 cup to top the cookies
Form the dough into 24 equal balls and place on a parchment lined cookie sheet. Flatten the dough balls slightly, and top with the reserved chocolate chunks
Bake for 13 minutes. Leave on the baking sheet until completely cooled
Top with flaky sea salt and enjoy