16ounceswhite chocolate baking barssuch as Baker's
¼cupsemisweet chocolate chipsmelted
Line a baking sheet with wax paper or parchment paper. Set aside.
Chop white chocolate baking bars into small pieces and place in a microwave-safe bowl. Microwave for 1 minute; stir chocolate well. Microwave for another 15 seconds; stir until chocolate is smooth. (If necessary, microwave in additional 15-second increments, stirring between each one, until chocolate is completely melted and smooth.)
Pour melted white chocolate onto the prepared baking sheet and spread it lightly to form an approximate 8- by 12-inch rectangle. Working quickly, arrange the pretzel twists all over the white chocolate, then fill in the spaces between the pretzels with the candy corn and peanuts. If desired, sprinkle the entire surface with sprinkles, pressing them lightly into the chocolate, if necessary.
Pour the semisweet chocolate chips into a small microwave-safe bowl. Microwave for 30 seconds, stir well. If necessary, microwave in additional 10-second increments, stirring between each, until chocolate is smooth and melted. Allow the melted chocolate to cool for a minute, then transfer to a disposable plastic baggie. Push chocolate down into one corner and snip off a tiny piece of that corner with scissors. Twist the top of the baggie and use it as a piping bag to drizzle the surface of the bark with thin parallel lines of chocolate.
Refrigerate until chocolate is set, about 45 minutes. Slide wax/parchment paper onto a cutting board and cut bark into pieces. Serve immediately or store in a tightly-sealed container in the refrigerator.