Heat oven to 350 F (180 C). Combine cookie crumbs, 1/2 cup (125 mL) peanuts, 1/4 cup (50 mL) granulated sugar and butter. Press into an ungreased 10-inch (23 cm) springform pan. Bake at 350 F (180 C) for 15 minutes; cool.
Beat 1 and 3/4 cups (425 mL) heavy whipping cream until stiff; set aside. In mixing bowl, beat together peanut butter and cream cheese until smooth. Stir in powdered sugar and vanilla mixing well. Fold in beaten whipping cream, adding in a quarter at a time. Pour into cooled crust and refrigerate until set, about 2 hours.
Combine remaining 1/4 cup (50 mL) granulated sugar and remaining 1/4 cup (50 mL) heavy cream in heavy small saucepan. Stir over medium heat until sugar dissolves and mixture comes to a simmer. Remove from heat and add chocolate pieces, stir until melted and smooth. Cool 5 minutes and spread evenly over filling. Sprinkle with remaining 1/2 cup (125 mL) chopped peanuts to garnish.
Refrigerate until cold, about 4 hours. Serve chilled.
Per Serving (1 slice per serving): 672 calories; 51 g carbohydrates; 14 g protein; 49 g fat (63% cal from fat); 76 mg cholesterol; 4 g fibre; 405 mg sodium