1. Prepare the Baking Sheet: Line a large baking sheet with parchment paper and set it aside.
2. Melt the Candy Melts: Place the white chocolate candy melts in a microwave-safe bowl. Heat them in the microwave according to package instructions, stirring every 20-30 seconds to ensure even melting.
3. Coat the Graham Crackers: Take one graham cracker at a time. Hold one end and dip the bottom into the melted white chocolate. Use a spatula to smooth the coating along the sides. Slide it out, shake off any excess, and place it on the parchment paper. Optionally, sprinkle with ground cinnamon. Repeat for all graham crackers.
4. Let Them Dry: Allow the coated graham crackers to dry for at least 30 minutes.
5. Prepare the Dip: In a stand mixer, beat the softened cream cheese and Cool Whip at medium speed until smooth (about 2 minutes).
6. Mix in Remaining Ingredients: With the mixer on medium, add powdered sugar, pumpkin puree, pumpkin pie spice, and vanilla extract. Beat until combined, around 3 to 5 minutes.
7. Serve: Transfer the dip to a serving bowl and sprinkle the top with ground cinnamon if desired. For added firmness, chill in the refrigerator for 30 minutes to 1 hour before serving.