Slit the shell of the chestnut on the rounded side. Dip in the very hot deep-frying pan for a few minutes until open. Drain. Thus you can remove both the skin and the shell very easily. Put the chestnuts into a stewpot with a pinch of salt and enough cold water just to slightly cover, simmer gently for 30 minutes. The chestnuts must be easy to mash with your fingers. Meanwhile, in the preserving pan, make a syrup with the sugar slightly moistened with cold water and the vanilla pods, halved lenghtways. Cook until regular large bubbles appear on the surface. Mash the drained chestnuts in a fine sieve. The finer the purÄe, the finer the jam. Do not allow to cool. Once the large bubbles appear on the surface of the syrup, add the purÄe to the syrup, cook for 30 to 35 minutes, stirring continuously. Fill the jars immediately, do not cover until the day after. Chill. This jam ferments easily, so to keep it for a long time, put into sterilizing jars immediately after bringing to a boil, then sterilize for 30 minutes.
