1. Combine pumpkin, sugar, cinnamon & nutmeg in a medium saucepan. Mix and allow to simmer. 2. Remove from heat and allow for the pumpkin mixture to cool down completely. 3. In a bowl, beat cream and vanilla until it forms semi-stiff peaks. 4. Fold pumpkin mixture into whipped cream. 5. Chill mousse in the fridge for about 1 hour and then use an electric beater to mix some more. 6. Garnish with graham crackers. Serve and enjoy!