Preheat your oven to 325 degrees. While the oven is preheating, put your pie crust in the pie dish, press aluminum foil into it, and fill the pan with coins to keep the pie crust weighted down. Bake the pie crust for 25 minutes.
Over medium high heat, bring the peanut butter, powdered sugar, and milk to a boil while stirring constantly. Once the mixture comes to a boil, continue cooking for two minutes, and then remove from the heat.
Whisk your egg yolks, and add a small amount of the peanut butter and milk mixture and whisk in.
Add the egg yolks to the saucepan with the rest of the peanut butter and milk mixture, and bring it back to a boil, stirring consistently. Continue cooking for two minutes.
Pour the peanut butter custard into the baked pie crust and and smooth out to make even. Let cool in the refrigerator overnight or for at least four hours.
When the pie has finished chilling, make your ganache.
Start by bringing the heavy cream to a boil, stirring consistently. Once it has come to a boil, pour it over the white chocolate. Stir vigorously until the mixture is smooth.
Pour the white chocolate ganache over the cooled pie and refrigerate for at least an hour.