Reserve 1/4 cup cookie crumbs. In a bowl combine remaining cookie crumbs and butter and press into bottom and side of a 10-inch (1 1/2 quart) pie plate. Chill shell.
In a heavy saucepan dissolve sugar in milk over moderate heat, stirring, and remove pan from heat. Whisk in peanut butter and vanilla until combined well and cool in a bowl set in a larger bowl of ice water, stirring occasionally.
In another bowl beat cream until it just holds stiff peaks and fold into peanut-butter mixture with chopped peanuts. Turn mixture into shell, smoothing top. Sprinkle reserved cookie crumbs around edge of pie.
Pipe rosettes of whipped cream decoratively onto crumbs and top rosettes with whole peanuts. Freeze pie, uncovered, until frozen hard, about 5 hours. Pie may be made 2 days ahead and frozen, covered with plastic wrap and foil after 5 hours.
Let pie stand in refrigerator 30 minutes before serving.
Garnish: lightly sweetened whipped cream and whole salted roasted peanuts.