In a medium bowl, mix together pumpkin puree, brown sugar, granulated sugar, cinnamon, nutmeg, and vanilla extract until smooth. Cover and refrigerate for 15-30 minutes.

Preheat your oven to 400°F (200°C). Roll out each puff pastry sheet to approximately 10x12 inches and cut into six equal rectangles.

Spoon about one tablespoon of the chilled pumpkin filling onto the center of each rectangle. Fold in half and seal the edges, then twist the edges together.

Place the twists on a parchment-lined baking sheet and brush with the egg wash. Bake for 15-20 minutes until golden brown.

Remove from the oven and let cool on a wire rack for 5-10 minutes before serving warm, dusted with powdered sugar.