Prepare the pumpkins: Cut a wide opening around the stem of each pumpkin and remove the top, leaving the pumpkin bodies intact to hold the filling. Scoop out the seeds and stringy flesh and discard. Cover the pumpkins with plastic wrap and refrigerate while you prepare the filling.
12 mini pumpkins
Heat the cream: In a medium saucepan over medium heat, bring the cream and sugar to a gentle boil, stirring occasionally. Reduce the heat to maintain a gentle simmer and cook for a full 7 minutes, stirring frequently. The cream can foam up quickly, so stay close and lower the heat as needed to keep it from boiling over. Don’t cut the simmer short, reducing the cream helps the possets set.
3 cups heavy cream, 3/4 cup granulated sugar
Finish the posset mixture: Remove the saucepan from the heat and whisk in the pumpkin puree, lemon juice, apple cider vinegar, vanilla bean paste, and pumpkin pie spice. Let the mixture cool for 10 minutes, then strain through a fine-mesh sieve into a bowl or large measuring cup with a pour spout.
1 cup pumpkin puree, 1/4 cup lemon juice, 2 Tablespoons apple cider vinegar, 1 Tablespoon vanilla bean paste, 1 1/2 teaspoons pumpkin pie spice
Fill and chill: Arrange the hollowed-out pumpkins upright in a rimmed baking dish so they sit level. Pour the posset mixture into the pumpkins, filling each just below the rim. Cover the dish with plastic wrap and refrigerate for at least 3 hours, preferably overnight, until set.
Serve: Top with whipped cream and a sprinkle of cinnamon sugar, and serve chilled.
For serving: whipped cream and cinnamon sugar