Preheat your oven to 350 degrees F (180 degrees C) and place the oven rack in the center of the oven. Line an 8 inch (20 cm) square baking pan with foil.

In a large bowl, mix together the Graham Cracker Crumbs, sugar, and melted butter. Press onto the bottom of the prepared pan. Place in the preheated oven and bake for about 10 - 12 minutes or until firm and just beginning to brown. Remove from oven and place on a wire rack to cool.

In the bowl of your electric stand mixer, fitted with the paddle attachment (or with a hand mixer), beat the butter until smooth. Add the peanut butter and beat until blended and smooth. Add the sugar, vanilla extract, and cream. Beat, on high speed, until light in color and soft and fluffy (about 2 to 3 minutes). Scrape down the sides and bottom of the bowl as needed. Pour the filling over the cooled crust and smooth the top. Cover loosely with plastic wrap and place in the refrigerator for about 2 hours or until firm.

Place the chopped chocolate in a medium sized heatproof bowl. Set aside. Heat the cream and butter in a small saucepan over medium heat. Bring just to a boil. Immediately pour the boiling cream over the chocolate and allow to stand, without stirring, for a few minutes. Stir gently until smooth. Let cool slightly and then pour the ganache over the peanut butter filling. Sprinkle with chopped peanuts, if desired. Cover and place in the refrigerator until chilled.