Preheat oven to 400F. Line cookie sheets with parchment paper and set aside.
Unroll the thawed puff pastry and use a rolling pin to roll out each sheet to about 8-inches by 14-inches.
Use a pumpkin shaped cookie cutter to cut out pumpkin shapes from the puff pastry.
. Lay half of the pumpkin shaped pieces of puff pastry on the prepared cookie sheets. Reserve the second half of the puff pastry pumpkins for later in the recipe.
In a small bowl, whisk together the pumpkin puree (be sure you’re using 100% pure pumpkin and not pumpkin pie filling), brown sugar, 1 egg, heavy whipping cream, 1 teaspoon of pumpkin pie spice, and the vanilla extract. Spoon the filling into the center of each of the pumpkin-shaped puff pastries on the cookie sheets.
Dip your finger or a pastry brush in water and lightly brush water around the edges of the puff pastry.
Use a small sharp knife to cut out jack-o-lantern faces on the second half of the pumpkin puff pastries, then top each pumpkin on the cookie sheets with a jack-o-lantern puff pastry top. Gently press around the edges to seal closed (the water will help the two pieces stick together).
In a small bowl, whisk together 1 egg with 1 tablespoon water. Use a pastry brush to gently brush this egg wash over the top of the puff pastry pumpkins.
In a small bowl, combine the granulated sugar with the remaining 1 teaspoon of pumpkin pie spice. Sprinkle the mixture over the pumpkins.
Bake at 400F for 13-15 minutes, until the jack-o-lanterns are puffed up and golden brown. Remove from the oven and transfer to a wire cooling rack to cool before serving.