Spray an 8×8 or 9×9-inch baking pan and then line it with foil or waxed paper.
In a large bowl, combine the peanut butter, molasses, and powdered sugar until blended. Stir in the cereal. It will be very thick.
In a microwave safe bowl, combine 1 cup of the white chocolate and 2 Tbsp. of the shortening. Microwave for 30 seconds then stir well. Microwave again in 15 second intervals, stirring after each time, until smooth and melted.
Pour the chocolate mixture into the prepared pan and spread out over the bottom of the pan and a little up each of the sides.
Place in the freezer for 10 minutes to set.
Remove from the freezer and spread the peanut butter mixture evenly into the pan.
Microwave the remaining 1/2 cup of white chocolate and the 1 Tbsp. of shortening until melted and smooth.
Pour over the top of the peanut butter mixture and spread evenly.