Spray an 8x8" baking dish with cooking spray. (Line with foil first for easy cleanup.) Preheat your oven to 350 degrees.

Combine butter, cocoa powder, and sugar in a medium sized saucepan. Over medium heat, whisk until melted and smooth. Let cool 5-10 minutes, then pour into a large mixing bowl.

To the cooled chocolate mixture, whisk in the eggs and vanilla extract.

Add the flour and salt, stir until no streaks of flour remain.

Pour into prepared pan and spread evenly. Bake at 350° for about 30 minutes. A toothpick inserted shouldn't come out wet, but moist crumbs are fine. Don't over bake if you want fudgy brownies!

Let cool for at least 15-20 minutes before slicing. But for easiest slicing, let them cool completely.