8 ounces good-quality white chocolate, melted and cooled
Line an 8-inch square baking pan with wax paper so that there is overhang on 2 sides. Spread half of the melted bittersweet chocolate in the pan and refrigerate just until set.
Meanwhile, in a medium bowl, combine the peanut butter, granola, chocolate chips and white chocolate and stir until smooth. Scrape the mixture into the pan and flatten to an even layer. Spread the remaining melted bittersweet chocolate on top and refrigerate until set. Unmold and cut into bars.