Sprinkle pecans in bottom of buttered 8 inch square baking pan. Combine butter and brown sugar in 2 quart heavy saucepan. Cook over medium heat, stirring constantly, until mixture comes to a boil. Continue cooking, stirring constantly, until mixture reaches hard crack stage (295F) on candy thermometer. Immediately pour hot mixture over pecans,spreading evenly. Sprinkle with chocolate pieces. Let stand 5 minutes. Spread melted chocolate evenly over all. When chocolate is set, break up into pieces. Makes about 3/4 of a pound. Origin: Farm Journal's Choice Chocolate Recipes Shared by: Sharon Stevens.