Saccharine and decadent, this sizeable pie has layers of dense peanut butter mousse and chocolate sponge cupped in a crust of Oreo crumbs; a smattering of baby marshmallows, choco pops and milk chocolate sauce lounge across the top. It would be overly cloying if not for the scoop of vanilla bean ice cream, which slices through the richness of the pie with icy coolness.