Preheat the oven to 350°F (175°C).
In a medium bowl, combine the crushed peanut butter cookies and granulated sugar.
Pour the melted unsalted butter over the cookie crumb mixture and stir until all crumbs are evenly coated and the mixture holds together when pressed.
Press the mixture firmly and evenly into the bottom and up the sides of a 9-inch (23 cm) round tart pan or pie dish to form the crust.
Bake the crust in the preheated oven for 12 minutes or until the edges are golden and set.
Remove the crust from the oven and let it cool completely before adding your desired filling.