Preheat oven to 350 degrees. Line 11 x 7 inch baking pan with nonstick foil.
Melt butter and chocolate in a microwave safe bowl and let cool a few minutes.
Stir the sugar into the butter/chocolate mix.
Add eggs one at a time.
Add vanilla.
Stir in flour and salt.
Spread batter evenly into the pan and bake 27-35 minutes.
Let cool completely and cut into squares.