In a large heavy sauce pan, whisk together the granulated sugar, cornstarch and salt.

Put the pan on medium heat.

Immediately add and whisk the milk and yolks (while burner is heating up).

Continue to keep whisking while the liquid is heating up for 10 to 15 minutes.

Once it starts to thicken and bubble, turn off burner and take the pan off the heat.

Add the vanilla, peanut butter, and cold butter pieces-- one by one while you are still stirring with your whisk.

Once the butter and peanut butter has melted, put into a bowl and cover with plastic wrap on the surface of the custard to prevent a skin forming. Make sure the wrap is touching the custard on the top.

Refrigerator until cooled (about 2-4 hours) or over night.

For the crust:

Stir together the finely crushed Oreo crumbs and melted butter in a large mixing bowl.

Pour the crumb mixture into a 9" springform pan or pie pan.

Use your hands or a flat-bottomed glass to press the crumb mixture evenly into the bottom and sides of the pan. Press firmly to pack down.

Pour half of the chilled custard into the pressed cookie crust. Layer with half of the peanut butter cups. Pour on the rest of the chilled custard and top with the rest of the peanut butter cups.

Cover and place in freezer until frozen. Serve and enjoy!

Store leftover frozen pie in the freezer for up to a week.