Microwave butter and chocolate, stir until smooth

Cool slightly

In a large bowl, beat sugar and eggs

Stir in vanilla and chocolate mixture

Combine flour and salt; gradually add to chocolate mixture

Sir in pecans if desired

Spread into two greased 8-in square baking pans.

Bake at 325 for 35-40 min or until a toothpick inserted near the center comes out clean.

Cool on a wire rack and dust with confectioners' sugar if desired.

Cut into bars.