Prepare the crust by combining the graham crackers and sugar in a large bowl, add the melted butter and mix into a coarse crumble.
Press the crust into the bottom of an 8 x 8 baking dish, lined with parchment paper.
Place in the freezer for 10 minutes.
In the meantime, prepare the cheesecake filling by using an electric hand mixer to combine the peanut butter, cream cheese, powdered sugar, milk and vanilla.
Blend until creamy, then use a large spoon or spatula to hand mix in the Reese’s Peanut Butter Cup pieces.
Remove the crust from the freezer, spread the cheesecake on top.
Place back into the freezer for at least 4 hours.
Remove 15-20 minutes before serving to thaw enough to slice through.