Chocolate Peanut Butter Ice box Cake

1. Put 4 ounces of chocolate in a microwave safe bowl and melt it in the microwave (heat it for only 30 seconds at a time, stirring between each additional 30 seconds). When melted, stir until smooth.
2. Whisk in the peanut butter and stir until smooth and slightly thick.
3. In a separate bowl, whip the whipping cream to soft peaks.
4. Whisk ¼ cup of whipping cream into the chocolate peanut butter mixture. When it is really smooth, whisk in another ¼ cup of the whipping cream.
5. Then add the chocolate peanut butter mixture into the remaining bowl of whipping cream and fold and stir until completely combined.
6. Line a standard size loaf pan with plastic wrap (2 sheets overlapping each other with plenty of excess hanging over the sides of the pan—you’re going to wrap it over the top of the crackers when done).
7. Line the bottom of the pan with graham crackers. If you need to cut the graham crackers to fit better, do so with a sharp knife, (they cut surprisingly easily).
8. Spread a dollop of the chocolate peanut butter filling completely over the graham cracker layer.
9. Now repeat these layers all the way to the top of the loaf pan and until the chocolate peanut butter is all used up.
10. The very top layer should be graham crackers. Then pull the plastic wrap up tight around the cake and place it in the refrigerator. Chill for at least 12 hours and up to several days.
11. To make the frosting (do this once the cake has fully chilled), melt 4 ounces of chocolate in the microwave the same way you did above and stir until smooth.
12. Whisk in the small pieces of butter until the chocolate and butter are smooth.
13. Whisk in the powdered sugar and mix until you have a smooth frosting. Set aside at room temperature.
14. Remove the cake from the refrigerator and transfer from the pan to a flat surface.
15. Unwrap the cake and transfer to a platter.
16. Using a small offset spatula or a butter knife, evenly spread the frosting over the graham cracker layers.
17. Continue to chill in the refrigerator for about 30 minutes.
18. Melt the 2 ounces of chocolate in a microwave as instructed above and stir until smooth. Using a fork, drizzle the chocolate over the top of the cake.
19. Using a sharp knife, slice the cake like a loaf of bread and if desired serve with a dollop of freshly whipped cream.