Melt the butter in a microwave safe bowl. Let it cool for just one minute. Pour it into your large mixing bowl.

Add the sugar to the melted butter. Whisk them together until they are smooth. The mixture should look shiny and pale.

Add the eggs and vanilla extract now. Whisk the mixture for two whole minutes. This creates a thin and crackly top.

Sift the flour and cocoa powder together. Gently fold them into the wet batter. Stop mixing once the flour disappears quickly.

Stir in the semi-sweet chocolate chips now. Pour the batter into your prepared pan. Spread it evenly with a small spatula.

Bake the brownies for twenty-five minutes. Do not overbake them or they dry out. The center should be slightly soft still.

Sprinkle the flaky sea salt over the top. Let them cool in the pan completely. Slice them into squares and serve them.