Preheat the oven to 350º (177ºC). Line a small baking sheet with parchment (or spray lightly with nonstick spray), then spread the pumpkin purée evenly onto the baking sheet with a spatula or the back of a spoon.
1 cup pumpkin purée1
Roast the pumpkin for 25-30 minutes until it has started to firm up, dry out, and turn darker orange. Remove from the oven and set it aside to cool for about 20 minutes. You can speed up this process by putting it in the refrigerator.
Meanwhile, prepare the whipped cream: pour the heavy cream and powdered sugar into a medium size bowl (if you plan on using a handheld electric mixer) or the bowl of a stand mixer fitted with the whisk attachment.
1 cup (240mL) heavy whipping cream,6 Tablespoons (45g) powdered sugar
Whip the heavy cream on medium-high speed until it becomes thick and frothy, then increase the mixer speed to high and beat the mixture until it becomes thick and billowy and the mixer leaves a distinct trail with its revolutions (medium peaks). Stop the mixer and set the whipped cream aside until you are ready to add the pumpkin.
When the pumpkin has cooled, scrape it off of the baking sheet and into a small bowl. Add the pumpkin pie spice and the vanilla, then stir or beat the mixture on low speed until it is smooth and all of the spice is incorporated and the pumpkin is smooth.
1 teaspoon pumpkin pie spice,½ teaspoon vanilla extract
Add the pumpkin to the whipped cream, then beat everything together on medium-low speed until there are no more orange streaks. Stop the mixer, then use a spatula to fold the mousse together a few more times to be sure everything is well-combined. It is ready to use immediately, but you can also chill it before serving.
Portion into dessert cups and add toppings (I suggest homemade whipped cream or pumpkin spice whipped cream or even coffee whipped cream for a PSL vibe) before serving. Store leftovers in the refrigerator for up to 3 days. See notes3 for freezing instructions.
