Preheat oven to 350 degrees F. Spray a 8x8" baking pan with nonstick cooking spray. Line with parchment paper with an overhang on the sides and spray again. This will make it easy to lift the brownies out of the pan after baking. Set the pan aside.

In a large microwave safe bowl, combine 1 cup of the chocolate chips and the butter. Place the bowl in the microwave and melt in 30-second increments, on high heat, stirring every 30 seconds until melted and smooth. This should take 1 minute or a little longer. Don’t over heat.

Stir in the brown sugar and granulated sugar and mix until smooth. Stir in the eggs and vanilla extract and mix until combined.

Add the cocoa, cornstarch, espresso powder, and sea salt. Stir until just combined. Stir in ¼ of the remaining chocolate chips.

Pour the brownie batter evenly into the prepared pan. Sprinkle the remaining chocolate chips and a little bit of sea salt over the top. Bake for 20 to 25 minutes or until an inserted toothpick comes out with a few moist crumbs.

Let the brownies cool for before cutting into squares.