Preheat oven to 325°. Line a 9x13 baking pan with parchment paper with a bit of overhang so they brownies can be easily removed after baking and cooling.
Melt chocolate and butter in a medium sauce pan over medium-low heat. Remove from heat.
Whisk both sugars into the chocolate mix. Add in eggs, one at a time, then add vanilla. Whisk until combined.
Stir in flour and salt until evenly incorporated and pour batter into prepared pan.
Bake 35-40 minutes until center is set and a toothpick placed 2 inches away from edge comes out clean.
Let brownies cool completely before removing from baking pan and cutting into squares.