Place the bittersweet chocolate and butter in a heatproof bowl over a pot of simmering water. Stir until fully melted, then remove from the heat.

Gradually whisk in the sugar and add the eggs one at a time, mixing after each addition. Add the cocoa powder and the pinch of salt.

Gently fold the flour into the mixture with a rubber spatula and add the mini chocolate chips.

Pour the mixture into a square 9x9-inch cake pan that has been butter and lined with parchment paper, ensuring that excess parchment paper is hanging off of both sides. Smooth the surface of the batter and bake at 350F for 60-80 minutes or until fully cooked.

Place the pan on a wire rack and allow the brownies to cool completely while still in the pan.

Remove the brownies and the parchment paper from the cake pan. Slice off the crust of the brownies and set them aside. Slice the remaining brownie into 9 rectangles. Sit the brownies upright onto one of the longer sides. Cut small pieces from the crust to resemble briefcase handles and stick them onto the top of rectangular brownies. The moisture from the brownies will help the handles stick.

Enjoy them just like this, or with some fresh fruit and a scoop of vanilla ice cream!