MAKE THE CHOCOLATE CRUST: Preheat the oven to 375°. In a medium glass bowl, combine the chocolate and butter and microwave at high power in 20-second intervals until the chocolate is melted. Stir well, then stir in the cookie crumbs. Press the cookie crumbs over the bottom of a 9-inch springform pan and 1 1/2 inches up the side. Bake the crust for 10 minutes, or until set; the crust will continue to firm up as it cools.
MEANWHILE, MAKE THE PEANUT BUTTER FILLING: In a large bowl, using a handheld electric mixer, beat the cream cheese with the peanut butter, sugar and vanilla extract until blended. In another large bowl, using the same beaters, whip the chilled cream until firm. Fold one-third of the whipped cream into the peanut butter mixture to loosen it, then fold in the remaining whipped cream and 1/2 cup of the chopped peanuts. Spoon the filling into the crust, smoothing the surface. Sprinkle lightly with salt and refrigerate until set, about 3 hours.
MAKE THE CHOCOLATE TOPPING: In a medium glass bowl, combine the chocolate with the heavy cream and microwave at high power in 20-second intervals until the chocolate is melted and the cream is hot. Stir the chocolate topping until blended, then let cool to barely warm, stirring occasionally.
4.Spread the chocolate topping over the peanut butter filling and refrigerate until just firm, about 15 minutes. Sprinkle the remaining 1/4 cup of chopped peanuts around the edge of the pie. Carefully run a thin knife around the pie crust to loosen it, then remove the springform ring. Using a sharp knife, cut the pie into wedges. Run the knife under hot water and dry it between each cut.