Place butter and chocolate in saucepan over low heat. Melt together over low heat, stirring constantly until smooth.
Remove from heat; stir in sugar, eggs, vanila, flour, and salt.
Pour batter into a greased and floured 8-inch square pan.
Bake @ 350° for 25 to 30 minutes, until firm and batter begins to pull away from pan.
Cool, cut into 2“ squares.