Line a 8" x 8" baking pan with aluminum foil , leaving at least 2 inches of foil overhanging on all sides (this will help you life the finished brownies out of the pan and eliminate messy pan clean-up). Set aside.

Melt chocolate and butter together in a heavy saucepan over medium heat, stirring constantly. Remove from heat and cool slightly.

Whisk sugar, vanilla and salt into chocolate mixture, followed by the eggs, one at a time. Continue whisking mixture until it is shiny and smooth. Add flour and whisk just until blended. Pour batter into prepared pan and level top. Bake for about 35 minutes, or until cake tester comes out with a few moist crumbs clinging to it. Cool completely in pan.