In a mixing bowl, add the heavy cream, ¼ cup of the powdered sugar, and 1 teaspoon of vanilla.
Use a hand mixer to beat the mixture—start on low speed to combine, then increase to medium high speed and whip until stiff peaks form. (That means when you lift the beaters, the cream stands up on its own.) Set this aside.
In another large bowl, add the softened cream cheese, peanut butter, the remaining ¾ cup of powdered sugar, and the remaining teaspoon of vanilla.
Beat the cream cheese and peanut butter mixture with the hand mixer on medium speed. It might look thick at first—kind of like cookie dough—but that’s okay! Just make sure it’s all mixed in.
Add two big tablespoons of the whipped cream to the peanut butter mixture and beat it in. No need to be gentle at this step. The cream helps lighten up the mixture so it’s easier to fold in the rest of the whipped cream later.
Now, gently fold the rest of the whipped cream into the peanut butter filling using a rubber spatula. Take your time and be gentle so you don’t lose all the fluff from the whipped cream. Keep folding until everything is combined, smooth, and no streaks remain.
Spoon the filling into the cooled chocolate crust and smooth out the top.
Cover loosely with plastic wrap, and chill the pie in the fridge for at least 5 hours or overnight until firm. Once the pie has set, slice and serve!