In a saucepan with medium heat, sweat onions in olive oil, then add garlic and cook until garlic turns golden brown. Add rosemary and cook for another minute.
Add in the chopped pumpkin, lower the heat and cook until it gets soft enough to puree
Once ready, dump everything into a food processor and puree until blended well, keep in the chiller to cool.
Preheat oven to 165ºC. Duck or poke all puff pastry sheets with a fork, cut the same size as your pie plate bottom and line the pie plate with the pastry. Once pumpkin mixture is cool, add 1 egg and mix well, season with salt and pepper.
Pour mixture over the puff pastry and sprinkle a generous amount of gorgonzola on top. Top with another layer of puff pastry cut the same size as your pie plate.
Lightly brush with egg wash, and bake in the oven for 1 hour and 15 minutes. Serve warm.