1. Heat oven to 350°F. Grease 8 or 9-inch square baking pan. Remove wrappers from chocolates. Cut each chocolate into 6 to 8 pieces; set aside.
2. Melt butter in saucepan over low heat. Add sugar and cocoa; stir to blend. Remove from heat. Stir in eggs and vanilla. Stir together flour, salt and baking soda; stir into chocolate mixture. Stir in chopped dark chocolates and nuts, if desired; spread in prepared pan.
3. Bake 25 to 30 minutes or until brownie starts to pull from edges of pan and is set. Cool completely in pan on wire rack. Cut into bars. Makes 16 brownies.