Cook your chestnuts in boiling salted water and then blend until creamy. Brown your mushrooms with the bacon, cut them into small pieces and add half of them to your chestnut cream. Melt your brie cheese in a small pan in a bain-marie and add the other half of the mushrooms you have browned with the bacon to your cream.

Cook your pasta in boiling salted water for 11 minutes, then drain all cooking water from the shapes (place them upside down on a clean tea towel).

Stuff Mushroom cap with your brie cheese cream and the stem with your chestnut cream, then assemble the two parts.