• Preheat oven to 350 degrees Fahrenheit (177 degrees Celsius).
• Line a 8x8”(20 cm) baking pan (glass or ceramic) with parchment paper, set aside.

Brown the Butter

• Cut butter into ½ “cubes.
• Put butter in a thick-bottomed pan (preferably in an even layer).
• Cook over medium heat, stirring occasionally,
• First, the butter will melt.
• Then, it will begin to foam on top and start bubbling.
• Next, it will start turning light brown with light brown flecks.
• Then, it will start turning a darker brown, amber color. At this point the butter is browned and cooking is complete.
• Immediately transfer the browned butter to a large mixing bowl.
• Let cool for at least 10 minutes, stirring occasionally.

Make the Dough

• Whisk in the white and brown sugar.
• Then whisk in egg and vanilla vigorously until the sugars are dissolved.
• Add flour, salt, baking soda and baking powder and stir until fully incorporated.
• Stir in the chocolate chips.

Bake, Cool & Serve

• Spread the batter evenly in the prepared baking dish. If desired, sprinkle the top with additional chocolate chips.
• Bake at 350 degrees F for 18 minutes, or until the top is set and the sides are just barely starting to brown
• Remove, sprinkle with flaky sea salt and let them cool in the pan on a wire cooling rack.
• Once cooled, use the parchment paper to lift the bars out of the pan, then cut into squares and serve.