To make the gravy: Soak the dried chestnuts overnight in cold water. The next day, drain the chestnuts and wash thoroughly.
In a medium-sized pot, bring the broth, stout, and molasses to a boil and add the chestnuts, thyme, bay leaf, and a pinch of salt and pepper.
Reduce the heat to a simmer and cook, uncovered, for 1 hour or until the chestnuts are soft. Remove the chestnuts with a slotted spoon, and set aside to be used later with the quail.
Continue to cook the liquid at a moderate boil for an additional 30 minutes or until the volume is reduced by half.
Add the crÃ¨me fraÃ®che or sour cream, and cook slowly for 3 to 5 minutes until the gravy begins to thicken and just coats the back of a spoon.
Taste for salt and pepper. The gravy may be made in advance and refrigerated, covered for 2 to 3 days.