In a medium skillet over medium heat, melt the butter and cream cheese together until smooth, about 2 minutes. Add the canned pumpkin puree, sweetened condensed milk, and pumpkin pie spice, stirring continuously for 5–7 minutes until the mixture thickens and is well combined.

Remove the skillet from heat and stir in the graham cracker crumbs and white chocolate chips until the mixture is completely smooth. Allow the mixture to cool slightly before transferring to the next step.

Pour the mixture onto a greased baking sheet, spreading it evenly to form a thick layer. Cover it with plastic wrap and refrigerate for at least 2 hours, or preferably overnight, until the filling is firm enough to handle.

Once the mixture is set, rub a bit of butter on your hands to prevent sticking, and scoop out golf-ball-sized portions of the filling. Roll each portion gently between your palms until they are smooth and round.

Pour granulated sugar into a shallow bowl and roll each truffle in the sugar until fully coated. Use a toothpick to create decorative ridges on the surface.

Arrange them on a festive platter for your gathering, or store them in an airtight container in the refrigerator until serving.