Sauté the diced, peeled, and seeded pumpkin with garlic and herbs. Cover with water and cook until very soft.
Remove the garlic and herbs and blend the pumpkin until smooth.
Mix the ricotta with the porcini mushrooms and Parmesan cheese (reserve some Parmesan for the topping).
Season with salt and pepper and fill a piping bag.
Prepare a thick béchamel by first toasting butter and flour, then adding hot milk and salt. Let cool.
Boil the cannelloni for 2 minutes, then stuff them with the ricotta mixture.
In a baking dish, spread a thin layer of béchamel, then add the stuffed cannelloni. Cover with more béchamel, pumpkin cream, and soaked and drained dried porcini mushrooms. Top with Parmesan and truffle cream.
Bake in a preheated static oven at 200°C for 20 minutes, finishing with 2 minutes under the grill if needed.
