Make the Crust: Combine the crushed Nutter Butter cookies and the melted butter until evenly moistened, and then press into a 9-inch pie pan. Place in the freezer while you prepare the filling.
Make the Filling: Using an electric mixer with a whisk attachment, beat the cream cheese, peanut butter, powdered sugar and 3 tablespoons of the heavy cream on low speed to combine, about 1 minute. Increase the speed to medium-high and whip until fluffy, about 1 additional minute. Transfer the mixture to a large bowl; set aside.
In the empty mixing bowl, add the remaining ¾ cup heavy cream and whip on medium-low speed until foamy, about 1 minute. Increase the speed to high and whip until stiff peaks form. Stir one-third of the whipped cream into the peanut butter mixture with a rubber spatula. Then add the remaining whipped cream in two additions, folding gently with a rubber spatula until no white streaks remain.
Transfer the peanut butter mousse into the prepared crust and spread into an even layer.
For the Whipped Cream: In the empty mixing bowl, add the heavy cream, powdered sugar and vanilla extract, and mix on medium-low speed until foamy, about 1 minute. Increase the speed to high and whip until stiff peaks form. Spread evenly over the peanut butter filling, cover with plastic wrap and refrigerate until set, at least 2 hours. When ready to serve, garnish with peanuts. Leftovers can be stored in the refrigerator, covered with plastic wrap, for up to 3 days.