Mise en place. Pour 4 C. of cereal into a large bowl. Pour the other 4 C. into a second large bowl. Pour 1 cup of powdered sugar into one large Ziploc bag.
Separate the Oreos, placing the cream filling in the bowl you're going to melt the white chocolate in. Crush the cookie wafer portions and place in a second large Ziploc bag. Add 1/2 C. powdered sugar to crushed cookies.
Add white chocolate- broken into chunks- into the bowl with the cream filling. Add 1 tsp. of the shortening. Melt in the microwave for 30 seconds at 50% power. Stir. Continue heating at 20 second intervals (at 50% power), stirring between each interval, until chocolate melted.
Pour the white chocolate and cream mixture over one of the bowls of cereal. Stir carefully, coating everything, trying not to break up cereal too much.
Add cereal to Ziploc bag that contains 1 cup of powdered sugar. Seal. Toss cereal, breaking up any chunks carefully, until everything is well-coated. Spread on a baking sheet to dry.
Place semisweet chocolate and remaining 1 tsp. of shortening into a small bowl. Melt in the microwave for 30 seconds at 50% power. Stir. Continue heating at 20 second intervals (at 50% power), stirring between each interval, until chocolate melted.
Pour the semisweet chocolate over the other bowl of cereal. Stir carefully, coating everything, trying not to break up cereal too much.
Add cereal to Ziploc bag that contains cookies crumbs and 1/2 cup of powdered sugar. Seal. Toss cereal, breaking up any chunks carefully, until everything is well-coated. Spread on a baking sheet to dry.
After everything is dried, toss together along with broken up Hershey's Cookies and Cream chocolate bars.
Hide any that you want to eat (it disappears fast!). Serve the rest.