Line the bottom of an 8 x 8 inch square pan with parchment or aluminum foil.
Mix the melted butter with the cracker crumbs, the one cup peanut butter and confectioner's sugar. Turn into prepared pan and spread evenly in pan. Chill for about 1 hour.
Place chocolate morsels, 2 tbs peanut butter and shortening in a microwave-safe bowl. Microwave on HIGH for 1 minute. Stir until mixture is smooth. You may have to return the bowl to the microwave for another 15-20 seconds if morsels are not completely melted.
Add the rice cereal to the chocolate mixture, stirring to coat well.
Spread on top of chilled peanut butter mixture and return to refrigerator to chill until firm, about 3 hours.