Filling
2 cups finely ground graham cracker crumbs, from about 13 whole crackers
1/2 cup pumpkin puree (not pumpkin pie filling)
4 ounces full-fat cream cheese, at room temperature
3 tablespoons firmly packed light brown sugar, or to taste
1 teaspoon vanilla extract
1 teaspoon pumpkin pie spice
1 teaspoon ground cinnamon
1/4 teaspoon salt
1 cup white chocolate chips
1 teaspoon vegetable oil
Coating
1 3/4 cups chocolate chips
1 tablespoon butter
finely chopped crystallized ginger (optional)
Directions
For filling, place graham cracker crumbs, pumpkin, cream cheese, brown sugar, vanilla, pumpkin pie spice, cinnamon, and salt in a large mixing bowl. Beat mixture with electric hand-mixer on medium-high speed until thoroughly smooth and combined, 1 to 2 minutes.
Place white chocolate chips and vegetable oil in a microwave-safe glass measuring cup or bowl. Heat in 15 second intervals, stirring after each, until chips are completely melted, about 45 seconds.
Pour melted white chocolate over graham cracker mixture and beat until thoroughly smooth and combined. Cover bowl, and refrigerate for at least 2 hours, or up to 24 hours.
Line a small baking sheet, cutting board, or plate that will fit into your freezer with parchment paper. Remove filling from the refrigerator. Scoop out 1 tablespoon filling and roll into a ball using lightly greased hands. Filling will be slightly sticky, but should still roll into balls. Place the filling ball on the prepared baking sheet; repeat with remaining filling.
Freeze filling balls until firm, at least 2 hours.
Place dark chocolate chips and butter in a microwave-safe bowl. Heat in 20 to 30 second intervals, stirring after each, until chocolate is melted and smooth, about 1 minute. Line a second baking sheet with parchment paper.
Remove filling balls from the freezer. Using a fork, lower a filling ball into melted chocolate and turn to coat. Lift out of the chocolate and gently tap the fork to remove the excess chocolate. Carefully slide truffle off the fork and onto the lined baking sheet. If desired, immediately sprinkle crystallized ginger over the top. Repeat with remaining truffles.
Refrigerate truffles until chocolate has firmed up, about 30 minutes. Store truffles, covered, in the refrigerator.